Well yeah, but (and I don't know if the 9250 is 4x or 8x) IF he wants to change his AGP multiplier for the purposes of general tinkering, then a tool he could try is Rivatuner; works with both ATI and nVidia GPUs.
The only incompatibility comes from AGP 8x/4x and 4x/2x I believe. 4x Cards I believe run at both 1.5V and 3V, whereas 8x cards would be 1.5V only. So a 4x card can be run in either type of slot.