Login as root - open up the "users and groups" dialog, highlight the user and select "remove" ... or just hit DEL key.
I'm not sure, but I don't think you can delete the last user account. i.e. you cannot run just the root user. (Indeed you shouldn't do this.)
There are a couple of things you may want to consider, since I've got your attention:
1. RH9 is legacy. But you know this right? Presumably you have a compelling reason to keep using RH9 in the face of all the amazing advancements in linux since.
2. It will aide you in future if you would edit your profile to show your distro and some hint to your location.