Apparently in our state (and our district especially) it's almost unheard of to place a child above grade level no matter the aptitude.
Our SD said the same thing, and we dragged in everyone, because they have a written policy for acceleration, so we tried to follow it. Turns out it's not possible unless some combo of parents/school or parents/district agree, and they flat out refuse to do so in any case.
And then we found the crack in the system, via word of mouth. It turns out that you can homeschool your child, then re-register them at the grade you say they should be, and they'll accept that at face value. DD's school offered no resistance at re-registering despite knowing full well what we'd done.
Maybe that can be your plan B.
