Do you have any achievement testing or work product from home which can illustrate to the school what level he is working on in math? In school testing would probably be best understood by the school.
While you can also share the WISC, it may be challenging to make your point with that alone. A child can have a high IQ or otherwise be high-ability, but be underachieving, so achievement testing may be more useful.
In my experience advocacy takes time and tons of patience, especially when you are advocating for outliers.
I apologize for your frustrations over Common Core math. We have had similar problems. I believe that it is challenging for teachers to truly differentiate when they are becoming familiar with the new standards themselves. Still, planning for advanced learners is something that is necessary. It is a misconception that the Common Core is challenging enough on its own - advanced learners will still need more.
