Good luck! It's hard at kindy age to expect a kid to do his own stuff. We lucked out and the GT coordinator offered to compact the 2nd grade curriculum for our DS and pull him out to teach it. We had gone in requesting that DS do EPGY, an online GT math program, while the other kids were doing math, but the GT teacher thought it was too dry for a kindergartner. She was amazing and somehow made the time to do this. It only lasted that one year, as she stepped down to teach full-time in the classroom, but we learned a few things. One, the school staff may surprise you with some good ideas; (2) you should really get any plan that is off the grid IN WRITING, and in that writing should be some notes of how the differentiation or compacting or acceleration should continue in future years (we didn't do this...), (3) try to look at this as a partnership and ASK ADVICE rather than DEMANDING something.

Some other thoughts - if there are math classes going on around the same time in 1st or 2nd grade, you could ask that your DS join those classes. You could investigate online math options if you think that would engage your DS and they have computers available. We offered to pay for whatever online class they might use. It helps to offer to help in any way you can.

Good luck!