I'm not sure if your advice is for kids good at math who want to eventually do something else, or kids that actually want to be mathematicians? I always thought

I'm not sure if your advice is for kids good at math who want to eventually do something else, or kids that actually want to be mathematicians? I always thought being a mathematician was something special in that there is ample historical evidence of very young prodigies in that field who made big contributions. Or are you saying top tier schools for math are so much better, that aspiring mathematicians should wait if at all possible to go to a top tier school? What if he's admitted at a top tier school at 9?