Have you visited the school? See if you can and get a sense of their day. Look at work examples and bring some things that represent what your son can do and see what they say about it.
My son did a charter that seemed to have a similar philosophy, kidnergarten was not a good fit at all. I found that applied to the other grades but kindergarten was very basic and that the individualization philosophy wasn't applied as well as I hoped, although I had it better than some others I know. Talk to a first grade teacher, go over the school day. We are reenrolling at the same school, which I was certain we would not do, after a very successful meeting with the first grade teacher. In retrospect I think our problem was a bad teacher fit, not a school fit.
