Just for background (or consideration if it turns out you really like the idea), you might like to take a look at the early entrance options available at the University of Washington's Robinson Center for Young Scholars:
https://robinsoncenter.uw.edu/programs/They have several levels of programs for differing age ranges and needs. This is a very well-developed early entrance support system, probably the best one in the country. The Transition School in particular is highly competitive, but you never know; if your kid ends up thinking it could be right for him when h for him when he's approaching the age range (7th/8th grade) you can support him in applying.
Definitely check out the Davidson Young Scholars program.
If any of this stuff had been around when I was that age I'd have totally jumped on it, regardless of what my parents might think of the notion. :-)
