OP,
Have you looked into putting the money into buying a house in Palo Alto, instead? My understanding is that the Palo Alto school district is superlative.

Re. private tutor, my concern would be that the kids would really bond to the person so you would have a major 'key person risk' on your hands versus a series of chosen online classes or a good school district which would spread some of that risk.

YMMV

Become what you are