builder-rhel8 image could use "native" python3.9 packaging
The builder-rhel8 image includes snippet-backported-python-rhel
via https://gitlab.com/cki-project/containers/-/blob/main/includes/pipeline?ref_type=heads#L31 . This means a prebuild python 3.9 binary installation is dropped into /usr/local/.
While rhel-8 by default uses python 3.6, the appstream repo does have a python3.9 package available so it might be nicer to use that and rely on the 'alternatives' tool or adjusting the python3 symlink to change the default interpreter.