Kubernetes Installer v2025.07.09-0 release notes (#3369)

Co-authored-by: replicated-ci-kurl <[email protected]>

Author: replicated-ci

docs/release-notes/rn-kubernetes-installer.md

@@ -10,6 +10,13 @@ This topic contains release notes for the [Replicated kURL](/vendor/kurl-about)
 
 <!--RELEASE_NOTES_PLACEHOLDER-->
 
+## v2025.07.09-0
+
+Released on July 9, 2025
+
+### New Features {#new-features-v2025-07-09-0}
+* Adds [EKCO add-on](https://kurl.sh/docs/add-ons/ekco) version 0.28.9.
+
 ## v2025.07.03-0
 
 Released on July 3, 2025