I don't know what you mean by an "access problem", but low wing airplanes generally make better balanced, and certainly more aerobatic, float planes. Plus, they are much more resistant to blowing over in a turn and usually don't require a water rudder. (I know you don't use a water rudder on snow, but if you don't fly it on water next summer you are going to miss out on a lot of fun.)

Your biggest concern should be wing loading. The floats will add 1 to 1 1/2 pounds to the weight of the plane. Your PC9 will start out with a pretty heavy wing loading and, with the floats on, it may not fly the way you like. The three I recommended all have a low wing loading to start with and, with floats on, they will fly about the same as the PC9 does without floats. My Graduate on Hobby Lobby floats weighed under 6 pounds and had a 625 sq. in. wing. That is a wing loading of 22 oz/sq. ft. on floats. I suspect that your PC9 is higher than that on wheels.

Jim