There isn't much difference between Redhat 9 and Fedora. The utilities are all virtually the same -- since they started in the same place. The RedHat 9 documentation should be true for virtually everything. For applicaiton-specific questions, read the man pages.
If you want my honest opinion, if this is a server and used for production, i'd think about loading an enterprise level OS on it such as CentOS.org, WhiteboxLinux.com or taolinux.org. You'll get much more life out of the system as these are all based off of RHEL 3 which has a minimum life of 5 years i think it is, as opposed to 3 - 6 month life with fedora cores, with extended support for another 3 - 6 months after the next core is released. Best of all the RHEL forks listed above are all free