Prepare release 1.9.0

Author: web-flow

CHANGELOG.md

@@ -17,6 +17,8 @@ Types of Changes:
 
 ## [Unreleased]
 
+## [1.9.0] - 2025-07-01
+
 ## [1.8.0] - 2025-05-23
 
 ## [1.6.4] - 2025-03-05
@@ -33,7 +35,8 @@ Types of Changes:
 
 ## [1.0.2] - 2023-09-14
 
-[unreleased]: https://github.com/LockedThread/gtsam_docker/compare/1.8.0...HEAD
+[unreleased]: https://github.com/LockedThread/gtsam_docker/compare/1.9.0...HEAD
+[1.9.0]: https://github.com/LockedThread/gtsam_docker/compare/1.8.0...1.9.0
 [1.8.0]: https://github.com/LockedThread/gtsam_docker/compare/1.6.4...1.8.0
 [1.6.4]: https://github.com/LockedThread/gtsam_docker/compare/1.6.3...1.6.4
 [1.6.3]: https://github.com/LockedThread/gtsam_docker/compare/1.6.1...1.6.3