Yes, I'm running RH9 and Gentoo.
In Gentoo everything has worked out-of-the-box.
In Redhat I had very much trouble getting the recording to work with ALSA 0.9.3 drivers. I found out, that I had in the KDE-taskbar the kmix-applet installed. As soon as I logged into KDE, the recording stopped to work. I also queried for a solution to this behaviour from the alsa-mailing list without any help. So I removed the kmix-applet and recording worked. This behaviour disappeared though, when I upgraded ALSA to 0.9.4
You could try to stop autoloading the snd-oss-mixer module and load it _just_ before you're trying to record something. And remember to setup the volumes to a proper level.