Prepare for release v1.9.

Author: vgvassilev

VERSION

@@ -1 +1 @@
-1.9~dev
+1.9

docs/ReleaseNotes.md

@@ -21,41 +21,60 @@ described first.
 External Dependencies
 ---------------------
 
-* Clad now works with clang-8 to clang-18
+* Clad now works with clang-9 to clang-19
 
 
 Forward Mode & Reverse Mode
 ---------------------------
-*
+* Improved differentiation support for complex mathematical expressions.
+* Enhanced function overload handling in both forward and reverse modes.
+* Enable differentiation when functions are defined in transparent contexts.
+
 
 Forward Mode
 ------------
-*
+* Optimized forward mode differentiation for performance improvements.
+* Added support for additional intrinsic functions.
+
 
 Reverse Mode
 ------------
-*
+* Enhanced handling of control flow structures in reverse mode.
+* Improved memory efficiency during differentiation.
+* Support member calls with xvalue bases in the reverse mode.
+* Initialize object adjoints using a copy of the original when copy constructor
+  is available. Eg:
+  ```
+  std::vector<...> v{x, y, z};
+  std::vector<...> _d_v{v}; // The length of the vector is preserved
+  clad::zero_init(_d_v); // All elements are initialized to 0
+  ```
+  The new clad::zero_init function relies on the iterators to initialize the
+  elements.
+
 
 CUDA
 ----
-*
+* Introduced experimental support for differentiating CUDA kernels.
+* Optimized CUDA differentiation to reduce compilation overhead.
 
-Error Estimation
-----------------
-*
 
 Misc
 ----
-*
+* General improvements in documentation and code clarity.
+* Various performance optimizations across Clad.
+* Improved `DiffRequest` and `DynamicGraph` printing.
+
 
 Fixed Bugs
 ----------
 
-[XXX](https://github.com/vgvassilev/clad/issues/XXX)
-
- <!---Get release bugs. Check for close, fix, resolve
- git log v1.8..master | grep -i "close" | grep '#' | sed -E 's,.*\#([0-9]*).*,\[\1\]\(https://github.com/vgvassilev/clad/issues/\1\),g' | sort
- --->
+[767](https://github.com/vgvassilev/clad/issues/767)
+[917](https://github.com/vgvassilev/clad/issues/917)
+[1082](https://github.com/vgvassilev/clad/issues/1082)
+[1112](https://github.com/vgvassilev/clad/issues/1112)
+[1215](https://github.com/vgvassilev/clad/issues/1215)
+[1216](https://github.com/vgvassilev/clad/issues/1216)
 
 Special Kudos
 =============
@@ -67,6 +86,11 @@ FirstName LastName (#commits)
 
 A B (N)
 
-<!---Find contributor list for this release
- git log --pretty=format:"%an"  v1.8...master | sort | uniq -c | sort -rn | sed -E 's,^ *([0-9]+) (.*)$,\2 \(\1\),'
---->
+Vassil Vassilev (36)
+petro.zarytskyi (12)
+mcbarton (2)
+PetroZarytskyi (2)
+dependabot[bot] (1)
+ToshitJain (1)
+Rohith Suresh (1)
+Abdelrhman Elrawy (1)