Going through the same thing. My 6 year old in first grade knows how to do double digit multiplication, division, fractions, etc. and is bringing home 5+2 math (at least it improved from the beginning of the year where it was 2+2--wow, they're moving right along!). At my request, the teacher gave him the second grade test and he passed it, so if he was to be subject accelerated, it should be 2 years. I would be happy with 1.
Subject acceleration won't work because of the "schedule" although I think it would if they really tried to figure it out. DS is supposedly doing an "enrichment packet"--but DS claims the math in the packet is the exact same math that everyone else is doing. Nothing is ever brought home so I have no idea what he's doing in school. Who knows what is really going on. I finally gave up and bought him a Singapore Math workbook at the third grade level, and he is doing a page or two every day after school. I tear it out and send it back in his folder, telling DS that his teacher assigned it to him (I told the teacher I was doing this--didn't ask, really--just informed her). My hope is that when he starts 2nd grade next year he can do a double skip for math. I plan to have him in a different school, maybe even in a different district. When I school-search, I will ask about this specifically.
DS informs everyone he doesn't learn anything in school, but he doesn't appear unhappy. If he was, I would probably be more pushy about accelerating him. Sorry I don't really have any advice. I think being as pushy I was, DS got a "packet" (maybe?)to do during independent work time, but that's as much as the teacher is going to do.