It depends on how far you're shooting. The vast bulk of my deer have been taken at 30 yds or less, with only a couple as far as 90 yds. A 6"/50yd group would be good enough for me under these circumstances. In fact, I've been quoted in the past as being happy with an 18"/100yd group for most of my hunting.
I normally don't shoot groups, but when I'm shooting at a 100 yd range, I find I'm satisfied with a 2 3/4 to 3 1/2 inch group. If your intended point of impact is in the centre of your group, a 9"/100yd group would mean a dead deer at that range.