Great Plan!

As an instructor, I've seen all the young ones come to the field with the "banging thumb" action they"ve picked up from gaming on the computer. When on the simulator, try to teach this from the start: Hold the stick by pinching it at the top with the thumb and indexfinger . Or, at least the thumb on top with the indexfinger close. I know, many of the best pilots out there are thumbs only, but I think starting out this way teaches control.

ARF is a great way to go and can involve a 9 year old totally in the process of getting everything together. There are lots of things to use basic tools on. You might consider getting the plane and flight equipment for the "Winter Project". This would give you guys plenty of time to work on it a little at a time, take trips to the Hobby Shop etc.. It's possible to get bored with the simulator, but with a plane sitting there, or hung from the ceiling, and dreaming of Spring, it doesn't get any better than that!
I'm sure this will be great no matter how you do it.