Rocky 9 doesn’t use init scripts because it is using systemd. I don’t believe Rocky 8 used it either. There may have been legacy support to allow init scripts in EL7 or EL8 but I cannot say for sure since EL7 was also the start of systemd in EL distros (RHEL6 was init script based). You should be looking at converting them to systemd service scripts and putting them under /etc/systemd/system and then using systemctl to enable/disable as well as start/stop/restart.
The /etc/rc.d/init.d I believe comes from the initscripts-service package being installed. Irrespective of the directories existing, you should still be using systemd scripts instead. There is no reason to use the old initd method.