We had the same thing with DD6 at the beginning of the year. She started kinder and went to 1st grade for reading with in 2 weeks. About a month later she went up for math as well. Then in the beginning of March she was moved up to 1st grade fulltime. She really only needed about a month of getting to know how to "do school" and then was pretty bored. She, however, is not the type to complain or act out - at least not at school. We saw a growing frustration level at home though and she got a real attitude at homw after especially slow days at school. Each time we would see something like this happening we asked for mor modification for her. Luckily, our school has been great in doing everything we've asked. In fact, they are also arranging for the district to do an IQ test at the end of this school year.
I think it depends on the child, but just watch to begin with and see how things play out. I would have another meeting with the kinder teacher though, and the principal to explain your fears/concerns before the end of this school year so they know what to watch for.
