I feel foolish because I figured it out right after posting, but I figured I'd share because it isn't intuitive and hopefully this will save someone some time.

The package you want to install is not gcc. You want to install gcc-toolset-9. You will notice after installation that you will still get 8.x if you do a gcc --version. gcc-toolset-9 installs to /opt. The idea is to give you a separate development environment. See this documentation. After installation you can run the updated gcc with /opt/rh/gcc-toolset-9/<username>/bin/gcc.

As @Stephen Kitt pointed out, you can actually get a shell with the updated toolset by running scl enable gcc-toolset-9 bash. Running this command will open a new bash session with the environment variables appropriately updated.

You can also run gcc v.9 directly with scl enable gcc-toolset-9 gcc <your_gcc_args>. See this documentation for details.

devtoolset is called gcc-toolset in RHEL8.

The following commands worked for me:

microdnf install -y gcc-toolset-12
scl enable gcc-toolset-12 bash
gcc --version
# gcc (GCC) 12.1.1 20220628 (Red Hat 12.1.1-3)

in a nutshell, here are some examples for how to install and configure

• for python3 to get python3.9: dnf install -y python39 && alternatives --set python3 $(command -v python3.9)
• for gcc to get gcc-12: dnf install gcc-toolset-12 && source scl_source enable gcc-toolset-12
• for java to get java-17: dnf install java-17 && bin_java_filename=$(rpm -qa|grep java-17|xargs rpm -ql|grep "bin\/java$"|head -1) && alternatives --set java ${bin_java_filename}
• tested on rocky8, rocky9

which repo has the newer software versions?

• the old method using "SCL" was deprecated
• the new method is to use a repo called "appstream"
• here is a post written by the distro maintainers explaining the change https://developers.redhat.com/blog/2018/11/15/rhel8-introducing-appstreams
• the repo is enabled by default

how to: install newer software versions?

• for python3: dnf install python39
• for gcc: dnf install gcc-toolset-12

how to: change the system default?

• for python3: alternatives --set python3 $(command -v python3.9)
• for gcc:
  • edit your user .bashrc or .bash_profile or create a new file under /etc/profile.d/ with the following: source scl_source enable gcc-toolset-12
  • i thought scl_source would go away in el8, el9 but apparently not
  • for more info on scl_source go to this link https://unix.stackexchange.com/a/195219/5510 or Permanently enable RHEL scl

p.s. what is the difference between alternatives and update-alternatives?

• the original tool is called update-alternatives and is from Debian linux distro
• in EnterpriseLinux, Redhat rewrote the tool and called it alternatives and when you install alternatives the package also installs a symlink with name update-alternatives on your env var PATH to help you find the tool
• the two are similar but not the same because their source code is different