We are still using RHEL8 based images to build the MCO containers and binaries (the MCD is an exception, which is doing a dual build).

We should switch to RHEL9 in 4.16 at the latest. Note that Hypershift is dependent on these binaries so the switch has to happen in conjunction. See #incident-hypershift-rhel-8-vs-9 on slack for context

Done when:

Hypershift-ci, FIPS-ci passing, RHEL workers