diff --git a/build/tcl/build.sh b/build/tcl/build.sh
index 2917cb4a9..df146e495 100755
--- a/build/tcl/build.sh
+++ b/build/tcl/build.sh
@@ -12,13 +12,13 @@
 # http://www.illumos.org/license/CDDL.
 # }}}
 
-# Copyright 2024 OmniOS Community Edition (OmniOSce) Association.
+# Copyright 2025 OmniOS Community Edition (OmniOSce) Association.
 
 . ../../lib/build.sh
 
 PROG=tcl
-VER=8.6.14
-EXPECTVER=5.45.4
+VER=9.0.1
+EXPECTVER=5.45.4.1
 PKG=ooce/runtime/tcl
 SUMMARY="Tool Command Language"
 DESC="A very powerful but easy to learn dynamic programming language"
@@ -28,16 +28,16 @@ MAJVER=${VER%.*}
 OPREFIX=$PREFIX
 PREFIX+=/$PROG
 
-set_builddir $PROG$VER/unix
-PATCHDIR+=-$PROG
+set_builddir $PROG$VER
+set_patchdir patches-$PROG
 
 SKIP_LICENCES=BSD-style
 
-# does not yet build with gcc 14
-((GCCVER > 13)) && set_gccver 13
-
 set_arch 64
 
+# the build requires gnu find
+PATH=$GNUBIN:$PATH
+
 XFORM_ARGS="
     -DPREFIX=${PREFIX#/}
     -DOPREFIX=${OPREFIX#/}
@@ -53,6 +53,12 @@ CONFIGURE_OPTS[amd64]="
     --enable-64bit
 "
 
+pre_build() {
+    append_builddir unix
+
+    unset -f pre_build
+}
+
 post_configure() {
     pushd $TMPDIR/$BUILDDIR/../doc >/dev/null
 
@@ -91,8 +97,11 @@ DESC="A tool for automating interactive applications"
 TCLDIR=$DESTDIR$PREFIX/lib
 PREFIX="$OPREFIX/$PROG"
 
-BUILDDIR=$PROG$VER
-PATCHDIR=patches-$PROG
+# does not yet build with gcc 14
+((GCCVER > 13)) && set_gccver 13
+
+set_builddir $PROG-$VER
+set_patchdir patches-$PROG
 
 SKIP_LICENCES=NIST
 
@@ -113,9 +122,10 @@ CONFIGURE_OPTS[amd64]="
 "
 
 init
-download_source $PROG $PROG$VER
+download_source $PROG $PROG $VER
 patch_source
 prep_build
+run_autoconf -f
 LD_LIBRARY_PATH=$TCLDIR build
 make_package $PROG-local.mog
 clean_up
diff --git a/build/tcl/files/ctf.ignore b/build/tcl/files/ctf.ignore
index d9b455970..2c740b630 100644
--- a/build/tcl/files/ctf.ignore
+++ b/build/tcl/files/ctf.ignore
@@ -3,4 +3,9 @@ exp_regexp.c
 itclTestRegisterC.c
 psGdbm.c
 psLmdb.c
+tclAlloc.c
+tclEpollNotfy.c
+tclKqueueNotfy.c
+tclThreadJoin.c
 threadNs.c
+threadUnix.c
diff --git a/build/tcl/patches-tcl/alloca.patch b/build/tcl/patches-tcl/alloca.patch
new file mode 100644
index 000000000..8a909d889
--- /dev/null
+++ b/build/tcl/patches-tcl/alloca.patch
@@ -0,0 +1,29 @@
+diff -wpruN --no-dereference '--exclude=*.orig' a~/pkgs/sqlite3.47.2/compat/sqlite3/sqlite3.c a/pkgs/sqlite3.47.2/compat/sqlite3/sqlite3.c
+--- a~/pkgs/sqlite3.47.2/compat/sqlite3/sqlite3.c	1970-01-01 00:00:00
++++ a/pkgs/sqlite3.47.2/compat/sqlite3/sqlite3.c	1970-01-01 00:00:00
+@@ -26,6 +26,11 @@
+ # define SQLITE_PRIVATE static
+ #endif
+ #define SQLITE_UDL_CAPABLE_PARSER 1
++
++#ifdef __illumos__
++#include <alloca.h>
++#endif
++
+ /************** Begin file sqliteInt.h ***************************************/
+ /*
+ ** 2001 September 15
+diff -wpruN --no-dereference '--exclude=*.orig' a~/pkgs/sqlite3.47.2/generic/tclsqlite3.c a/pkgs/sqlite3.47.2/generic/tclsqlite3.c
+--- a~/pkgs/sqlite3.47.2/generic/tclsqlite3.c	1970-01-01 00:00:00
++++ a/pkgs/sqlite3.47.2/generic/tclsqlite3.c	1970-01-01 00:00:00
+@@ -60,6 +60,10 @@
+ #include <errno.h>
+ #include "sqlite3Uuid.h"
+ 
++#ifdef __illumos__
++#include <alloca.h>
++#endif
++
+ /*
+ ** Some additional include files are needed if this file is not
+ ** appended to the amalgamation.
diff --git a/build/tcl/patches-tcl/makefile.patch b/build/tcl/patches-tcl/makefile.patch
index 8c9d7125e..5fdc611fc 100644
--- a/build/tcl/patches-tcl/makefile.patch
+++ b/build/tcl/patches-tcl/makefile.patch
@@ -3,9 +3,9 @@ man3 and mann).
 
 This patch will not be sent upstream.
 
-diff -wpruN --no-dereference '--exclude=*.orig' a~/Makefile.in a/Makefile.in
---- a~/Makefile.in	1970-01-01 00:00:00
-+++ a/Makefile.in	1970-01-01 00:00:00
+diff -wpruN --no-dereference '--exclude=*.orig' a~/unix/Makefile.in a/unix/Makefile.in
+--- a~/unix/Makefile.in	1970-01-01 00:00:00
++++ a/unix/Makefile.in	1970-01-01 00:00:00
 @@ -72,10 +72,10 @@ MAN_INSTALL_DIR		= $(INSTALL_ROOT)$(mand
  MAN1_INSTALL_DIR	= $(MAN_INSTALL_DIR)/man1
  
@@ -19,16 +19,16 @@ diff -wpruN --no-dereference '--exclude=*.orig' a~/Makefile.in a/Makefile.in
  
  # Path to the html documentation dir:
  HTML_DIR		= @HTML_DIR@
-@@ -286,7 +286,7 @@ CC_SWITCHES = $(STUB_CC_SWITCHES) ${NO_D
+@@ -285,7 +285,7 @@ CC_SWITCHES = $(STUB_CC_SWITCHES) -DBUIL
  
- APP_CC_SWITCHES = $(CC_SWITCHES) @EXTRA_APP_CC_SWITCHES@
+ APP_CC_SWITCHES = $(STUB_CC_SWITCHES) @EXTRA_APP_CC_SWITCHES@
  
 -LIBS		= @TCL_LIBS@
 +LIBS		= @TCL_LIBS@ -lc
  
  DEPEND_SWITCHES	= ${CFLAGS} -I${UNIX_DIR} -I${GENERIC_DIR} \
  	${AC_FLAGS} ${EXTRA_CFLAGS} @EXTRA_CC_SWITCHES@
-@@ -1028,7 +1028,7 @@ install-msgs:
+@@ -1146,7 +1146,7 @@ install-msgs:
  	done
  
  install-doc: doc
@@ -37,24 +37,23 @@ diff -wpruN --no-dereference '--exclude=*.orig' a~/Makefile.in a/Makefile.in
  	    if [ ! -d "$$i" ] ; then \
  		echo "Making directory $$i"; \
  		$(INSTALL_DATA_DIR) "$$i"; \
-@@ -1038,13 +1038,13 @@ install-doc: doc
+@@ -1156,13 +1156,13 @@ install-doc: doc
  	@for i in $(TOP_DIR)/doc/*.1; do \
  	    $(SHELL) $(UNIX_DIR)/installManPage $(MAN_FLAGS) $$i "$(MAN1_INSTALL_DIR)"; \
  	done
 -	@echo "Installing and cross-linking C API (.3) docs to $(MAN3_INSTALL_DIR)/"
 -	@for i in $(TOP_DIR)/doc/*.3; do \
 -	    $(SHELL) $(UNIX_DIR)/installManPage $(MAN_FLAGS) $$i "$(MAN3_INSTALL_DIR)"; \
--	done
--	@echo "Installing and cross-linking command (.n) docs to $(MANN_INSTALL_DIR)/";
--	@for i in $(TOP_DIR)/doc/*.n; do \
--	    $(SHELL) $(UNIX_DIR)/installManPage $(MAN_FLAGS) $$i "$(MANN_INSTALL_DIR)"; \
 +	@echo "Installing and cross-linking C API (.3tcl) docs to $(MAN3TCL_INSTALL_DIR)/"
 +	@for i in $(TOP_DIR)/doc/*.3tcl; do \
 +	    $(SHELL) $(UNIX_DIR)/installManPage $(MAN_FLAGS) $$i "$(MAN3TCL_INSTALL_DIR)"; \
-+	done
+ 	done
+-	@echo "Installing and cross-linking command (.n) docs to $(MANN_INSTALL_DIR)/";
+-	@for i in $(TOP_DIR)/doc/*.n; do \
+-	    $(SHELL) $(UNIX_DIR)/installManPage $(MAN_FLAGS) $$i "$(MANN_INSTALL_DIR)"; \
 +	@echo "Installing and cross-linking command (.1t) docs to $(MAN1T_INSTALL_DIR)/";
 +	@for i in $(TOP_DIR)/doc/*.1t; do \
 +	    $(SHELL) $(UNIX_DIR)/installManPage $(MAN_FLAGS) $$i "$(MAN1T_INSTALL_DIR)"; \
  	done
  
- install-headers:
+ # Public headers that define Tcl's API
diff --git a/build/tcl/patches-tcl/man.patch b/build/tcl/patches-tcl/man.patch
index 7c0295898..98f845bda 100644
--- a/build/tcl/patches-tcl/man.patch
+++ b/build/tcl/patches-tcl/man.patch
@@ -1,7 +1,7 @@
-diff -wpruN --no-dereference '--exclude=*.orig' a~/installManPage a/installManPage
---- a~/installManPage	1970-01-01 00:00:00
-+++ a/installManPage	1970-01-01 00:00:00
-@@ -87,8 +87,8 @@ fi
+diff -wpruN --no-dereference '--exclude=*.orig' a~/unix/installManPage a/unix/installManPage
+--- a~/unix/installManPage	1970-01-01 00:00:00
++++ a/unix/installManPage	1970-01-01 00:00:00
+@@ -102,8 +102,8 @@ fi
  
  case $ManPage in
      *.1) Section=1 ;;
diff --git a/build/tcl/patches-tcl/series b/build/tcl/patches-tcl/series
index df9d2c605..36f466373 100644
--- a/build/tcl/patches-tcl/series
+++ b/build/tcl/patches-tcl/series
@@ -1,2 +1,3 @@
 man.patch
 makefile.patch
+alloca.patch
diff --git a/doc/packages.md b/doc/packages.md
index a2e464857..6aeb15409 100644
--- a/doc/packages.md
+++ b/doc/packages.md
@@ -185,7 +185,7 @@
 | ooce/network/znc		| 1.9.1		| https://znc.in/releases/ | [omniosorg](https://github.com/omniosorg)
 | ooce/ooceapps			| github-latest	| https://github.com/omniosorg/ooceapps/releases | [omniosorg](https://github.com/omniosorg)
 | ooce/print/cups		| 2.4.11	| https://github.com/OpenPrinting/cups/releases | [omniosorg](https://github.com/omniosorg)
-| ooce/runtime/expect		| 5.45.4	| https://sourceforge.net/projects/expect/files/Expect/ | [omniosorg](https://github.com/omniosorg)
+| ooce/runtime/expect		| 5.45.4.1	| https://wiki.tcl-lang.org/page/Porting+extensions+to+Tcl+9 https://sourceforge.net/projects/expect/files/Expect/ | [omniosorg](https://github.com/omniosorg)
 | ooce/runtime/gnu-smalltalk	| 3.2.5		| https://ftp.gnu.org/gnu/smalltalk/ | [omniosorg](https://github.com/omniosorg)
 | ooce/runtime/groovy-30	| 3.0.21	| https://groovy.apache.org/download.html | [omniosorg](https://github.com/omniosorg)
 | ooce/runtime/groovy-40	| 4.0.21	| https://groovy.apache.org/download.html | [omniosorg](https://github.com/omniosorg)
@@ -197,7 +197,7 @@
 | ooce/runtime/ruby-32		| 3.2.6		| https://www.ruby-lang.org/en/downloads/ | [omniosorg](https://github.com/omniosorg)
 | ooce/runtime/ruby-33		| 3.3.7		| https://www.ruby-lang.org/en/downloads/ | [omniosorg](https://github.com/omniosorg)
 | ooce/runtime/ruby-34		| 3.4.1		| https://www.ruby-lang.org/en/downloads/ | [omniosorg](https://github.com/omniosorg)
-| ooce/runtime/tcl		| 8.6.14	| https://sourceforge.net/projects/tcl/files/Tcl/ https://www.tcl.tk/software/tcltk/download.html | [omniosorg](https://github.com/omniosorg)
+| ooce/runtime/tcl		| 9.0.1		| https://sourceforge.net/projects/tcl/files/Tcl/ https://www.tcl.tk/software/tcltk/download.html | [omniosorg](https://github.com/omniosorg)
 | ooce/security/gnupg		| 2.4.7		| https://gnupg.org/download/ | [omniosorg](https://github.com/omniosorg)
 | ooce/security/minisign	| 0.12		| https://github.com/jedisct1/minisign/releases | [omniosorg](https://github.com/omniosorg)
 | ooce/security/oath-toolkit	| 2.6.12	| https://download.savannah.nongnu.org/releases/oath-toolkit/ | [omniosorg](https://github.com/omniosorg)