In terms of the CCSS math changes, we have seen our local schools remove acceleration, only to find they needed to add it back in as the CCSS were not so horribly rigorous for the top students. The schools now offer a compacted 6th/7th class.
Don't most of the CCSS math classes now incorporate some pre-H.S. geometry into each year?
With that math RIT on the 2-5, he is well into the range where we have to wonder how well that version of the test is actually measuring him (and our schools do the same, btw). NWEA would appear to recommend that students in that range take the 6 grade and above test. Still, some of the students in that RIT range in our schools go into 6th grade math that will begin to accelerate in 7th, while others with additional high test scores will go into the accelerated/compacted 6th/7th class.
If you decide to do AoPS, I would not skip the pre-algebra class without giving it a close look. It is fairly challenging, perhaps, in some cases, even more so than a standard algebra class. DD did learn to solve challenging problems while doing AoPS!
