Les,
Let him learn with the scope. As has been said by others, keep it fun. When he becomes proficient with the scope, ask him if he'd like a little more challenge that will make him a better shot, and do it in the devious way a father does to influence his child. Don't rush the change-over, and let him have a good time. I'm of the opinion that a nice revolver, like a S&W 617 or a DW would be in order when he shows he can shoot with iron sights. I DO NOT believe in teaching HUNTERS to shoot with autos. I love my autos, but they are rather limited (with a few notable exceptions that likely don't apply) in the hunting arena. Almost every hunting-class handgun that is not a single shot will be a revolver, so that is the natural route in my opinion. Keep it fun, keep it simple, and enjoy the time with your boy. He'll be so big, so fast, and interested in things that aren't nearly as good for him as hunting and shooting that you'll thank youself for spending the time and having the fun that doesn't involve all the bad things that a youngster can get himself into.