Drop testing on 3.9

Author: danielhollas

.github/workflows/ci.yml

@@ -87,7 +87,7 @@ jobs:
 
         strategy:
             matrix:
-                python-version: ['3.9', '3.12']
+                python-version: ['3.12']
                 # Test latest and oldest supported package versions
                 uv-resolution: ['lowest-direct', 'highest']
             fail-fast: false