GNU/Linux Rocky 9 Enabling Dnf CRB Repo
How to Add Code Ready Builder Dnf Repository on Rocky Linux 9 GNU/Linux – Step by step Tutorial.
And PowerTools/CRB Repo for Rocky Linux 9 provides most of the Developer Tools.

1. Terminal QuickStart
How to QuickStart with Command Line on Rocky Linux 9
2. Enabling CRB Repo
Finally, to Add CRB/PowerTools Dnf Repository
Install the required tool with:sudo dnf install dnf-plugins-core
And then enable the repo:sudo dnf config-manager --set-enabled crb