docs: Add release notes for v9.0.9

DIRACGrid CI · DIRACGrid CI · commit 8e2628640d4a · 2025-11-19T19:06:43.000Z
diff --git a/release.notes b/release.notes
@@ -1,3 +1,7 @@
+[v9.0.9]
+
+CHANGE: (#8359) Subprocess: use psutil for killing processes
+
 [v9.0.8]
 
 *DataManagementSystem
