My DS9 recently got back his NWEA scores.

Math 274
Reading 243 Lexile 1375

I know he's in the 99th percentile and he exceeds the grade norm ranges for 3rd graders. I've tried to find materials online that provide context for these scores and have struggled. I want to be able to talk intelligently with the school about next steps and how I can properly supplement at home. He is already in a special program that groups kids by age but accelerates based on abilities - however I feel as if I need to do more to make sure he stays interested. Appreciate your help!