1. Antect ( I think it will work with 9600GT)
2. EvelCool (weird looking but at least it says supports all nVidia/ATI)
3. Scythe USA SCVMS-1000 Sleeve VGA Cooler (probably a better solution and specifically list 9600 as supported)
Installation pdf here
I'd advise running the card briefly to heat/warm it up. It will make the thermal grease that attaches the heatsink to the GPU more pliable/softer. Trying to take the heatsink assembly off the GPU chip when cold may require a bit of force-which could damage the chip or the traces leading from it.