The amount of software you install will NOT slow down your system. Unlike most other OSes, linux programs don't start automatically, unless you configure them to do so.
Also, RH9 is 5 years old, and no longer supported. You should not use it. If you like it, use Fedora Core 4, which is the newest version of Red Hat.
Also, you can't reinstall the OS when it is running, same as in Window$. If you want to format and reinstall, put disk 1 in, reboot, and boot to CD. When it says it detects a version of RH9, tell it to delete it. Game Over.