Hello
Did RL9 have a cinnamon version?
There is a Cinnamon live image available since a few weeks, with which you can also directly install it on disk.
The packages are coming from EPEL, so if you want install the Cinnamon DE yourself on a already existing machine you will get the packages from there.
https://dl.rockylinux.org/pub/rocky/9/live/x86_64/
https://rhel.pkgs.org/9/epel-x86_64/cinnamon-5.6.7-1.el9.x86_64.rpm.html