Is this a full-day Kindergarten? If so, is there a possibility that you could homeschool for a partial day, and send him there during the "social" activities? Our kindergarten did the reading/math in the morning and then specialists, science, etc. were in the afternoon. Most parents who opted to send their kid half day rather than full day, sent them for the reading, math, etc. but maybe you could do that the other way around.
That being said, even the science, social studies curriculum will probably be too easy. They will probably learn about the life cycle of a caterpillar. And what a community is. Even fourth graders don't seem to have much of a "history" curriculum. But at least it's not as painful as sounding out "cat" everyday.
