Add 2.9.0 release notes (opensearch-project#350)

Signed-off-by: Junqiu Lei <junqiu@amazon.com>

Author: junqiu-lei

CHANGELOG.md

@@ -12,7 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Maintenance
 ### Refactoring
 
-## [Unreleased 2.x](https://github.com/opensearch-project/geospatial/compare/2.8...2.x)
+## [Unreleased 2.x](https://github.com/opensearch-project/geospatial/compare/2.9...2.x)
 ### Features
 ### Enhancements
 ### Bug Fixes

release-notes/opensearch-geospatial.release-notes-2.9.0.0.md

@@ -0,0 +1,9 @@
+## Version 2.9.0.0 Release Notes
+
+Compatible with OpenSearch 2.9.0
+
+### Maintenance
+Increment version to 2.9.0-SNAPSHOT ([#329](https://github.com/opensearch-project/geospatial/pull/329))
+
+### Refactoring
+Change package for Strings.hasText ([#314](https://github.com/opensearch-project/geospatial/pull/314))