sndconfig does cannot use irq 9. I have a soundblaster 16 which had been configured to use irq 9. The sound config would not let me enter this. I had to edit the modules.conf by hand
On a system running 5.2 using sndconfig-0.27-1, I have not been able to replicate this problem. I am able to choose IRQ 9 in the list of IRQ's for the SoundBlaster16. After exiting sndconfig I checked the /etc/conf.modules and the proper parameters were added.
Problem is fixed in version 5.2, but I submitted the problem for version 5.1 so look for the fix in a patch.
Check the FTP site for the updated sndconfig RPM: sndconfig-0.27-1.i386.rpm.