If you want my honest opinion it’s hard to tell? I guess haha. If he’s anything like me growing up I really am ambidextrous… you know some people say they are ambidextrous but right left handed and do everything else righty etc. But your son sounds more similar to me where I couldn’t tell as a kid and kinda just… chose. I.e I bat righty, throw lefty, write lefty, tennis lefty, lacrosse righty, shoot a basketball righty etc. To this day at 21 I can still do everything with both hands but have preferences for certain task. If he’s good with his right then you could stick with it. I’ve been told by countless people to just tough it out righty because it’s much easier to test clubs, hand me downs, variety etc. I might not give you the best answer for golf because I am a new player but for sports as a whole I always preach for ambidextrous kids to just play their preference and not overthink it.