Just fyi, we were notified on April 10th last year - and yes, it was after the Feb test takers.
In IL, there is a state ceremony, but unfortunately, it is sponsored by IMSA and they only invite 7th and 8th graders.
We did not end up going to the ceremony, but my son went with his godmother (our oldest daughter graduated from college on the same day) and he seemed to like it. The ceremony itself was somewhat long and the talk was probably over his head (a reproductive gynecological oncologist of sorts, who went into great detail - which resulted in an apology from NUMATS and a very educational conversation with him afterwards,lol!!).
Anyway, your sons scores are great and I hope he gets invited!