Drop support for python 3.9

Author: tpaviot

azure-pipelines.yml

@@ -13,27 +13,6 @@ schedules:
   always: true
 
 jobs:
-- template: conda-build.yml
-  parameters:
-    name: Ubuntu_22_04_python39
-    vmImage: 'ubuntu-22.04'
-    py_maj: 3
-    py_min: 9
-
-- template:  conda-build.yml
-  parameters:
-    name: macOS_12_python39
-    vmImage: 'macOS-latest'
-    py_maj: 3
-    py_min: 9
-
-- template:  conda-build.yml
-  parameters:
-    name: Windows_VS2022_python39
-    vmImage: 'windows-2022'
-    py_maj: 3
-    py_min: 9
-
 - template: conda-build.yml
   parameters:
     name: Ubuntu_24_04_python310