Parallax error should be reasonably small, even at 9x. If you're holding the rifle correctly, there should actually be almost zero parallax error.
Really, the parallax error should be smaller than your rifle is capable of shooting. The only real side-effect is that objects closer than 100yds may appear a bit blurry in the scope. The closer and the higher the magnification, the blurrier. But I wouldn't worry about it.