950 gph isn't bad at all for a return pump on a 90 gal IMO. Just make sure the pump you are using is safe for saltwater use as you don't want the thing to rust out on you.
No problem...I was actually wondering which pump you were referring to as I never heard of a magdrive being reffered to as a 9.5b utility pump. The magdrive 950 was actually the one I used on my 90 gal as well. Also used it on my 75 gal and 38 gal.
mag drive pumps are ok... but they are loud and run hot, heating ur water...
for a 90g aquarium sump return pump, i would suggest the eheim 1260,
it is very quiet, no extra heat, and will last 10 years if u take care of it.
+1 on the heat. I've had one or two add a bit of heat to my tanks, but in all honesty, you can't beat what you get for the price going with a magdrive. I'll also agree with Mark as well on the Eheims. They seems to be the pump of choice these days.