I honestly do think a lot of it hogwash and worry that my son would be seen as problematic due to his high ability.
We looked at the local Waldorf for our youngest because they had a good reputation for working with food allergies. The director looked at my kid like he was damaged because he could read and even worse, do second grade math. Her look said we OBVIOUSLY must have pushed him. Uh, no, he just has older siblings and he's gifted. She also gave us her lecture about no plastic toys, not even lego (a deal breaker for DS), and no electronic media of any sort -- our one family movie a week was unacceptable. I decided that I just couldn't go along with it. Some schools are more strict than others.
I would ask them straight out how they would view your child given his high abilities. You don't want him getting the message that there is something wrong with him or that you are not good parents because he can read, write, etc. Maybe your Waldorf would be more accepting.