4.9 has already shipped, so aim for 4.9.z. And not a regression since 4.9.0 (the current behavior is old code), so blocker-.
oc get clusterversion
NAME VERSION AVAILABLE PROGRESSING SINCE STATUS
version 4.9.0-0.nightly-2021-10-25-231142 True False 11m Cluster version is 4.9.0-0.nightly-2021-10-25-231142
oc get clusteroperators | grep kube-storage
kube-storage-version-migrator 4.9.0-0.nightly-2021-10-25-231142 True False False 37m
oc describe co/kube-storage-version-migrator | grep -B 3 Upgradeable
Message: All is well
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory (OpenShift Container Platform 4.9.5 bug fix update), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.