This appears to have been raised in this post, but as far as I can tell it has not been addressed and as the OP mentions, the repo still doesn’t have the common package. I also don’t see it in devel which is the accepted answer in the other thread?
[root@patches 172.16.192.129-2024-07-23-15:13:11]# sudo dnf config-manager --set-enabled devel
[root@patches 172.16.192.129-2024-07-23-15:13:11]# sudo dnf clean all
25 files removed
[root@patches 172.16.192.129-2024-07-23-15:13:11]# sudo dnf repoquery kernel-debuginfo-common
Rocky Linux 9 - BaseOS 1.7 MB/s | 2.3 MB 00:01
Rocky Linux 9 - AppStream 11 MB/s | 7.9 MB 00:00
Rocky Linux 9 - Devel WARNING! FOR BUILDROOT ONLY DO NOT LEAVE ENABLED 13 MB/s | 14 MB 00:01
Rocky Linux 9 - Extras 19 kB/s | 15 kB 00:00
[root@patches 172.16.192.129-2024-07-23-15:13:11]# sudo dnf repoquery kernel-debuginfo-common
Last metadata expiration check: 0:00:03 ago on Tue 23 Jul 2024 03:51:23 PM EDT.