Enrique,
While for such uses I certainly prefer more power and parallax adjustment, a 3-9 can certainly get the job done. If for some reason you don't like/want higher power or sidefocus don't be afraid of a good 3-9--especially since you always have giant binoculars around so you won't need the scope to count points on the rack or anything.
Personally I do better with higher power; seeing the target a bit better, eliminating parallax completely and it helps me judge the wind. But a guy can get a lot done with a really good 3-9 (the SS is my current favorite).
Of course the best idea is to try it with both and see how much a difference it makes to you.
