I really doubt you'll find any notable improvement by going to higher magnification. A bigger objective lens might help in low-light conditions during the first half-hour or last half-hour of shooting light, but not all that much, really. It won't help at night, from what I've observed first-hand in my own varmint hunting.
If your group-center does not change as you go from 3 to 9 (3 shots at 3-power; change to 9-power and shoot 3 more) you're about as good as you're gonna get, unless the scope falls apart...
Sur, there are better and fancier scopes, but what you have is good enough, this side of prairie dogs at 400 yards...
Regards, Art