Yes, Hayes Grier is currently in the 8th grade (2014), but he'll be moving on to high school pretty soon.
It's been a good year for the Magcon boys, and you can see just how good in the following video:
Is Hayes Grier in 8th grade?
I have been in middle school with Hayes Greyer, and I can confirm that as I am writing this he is in 8th grade.
There was talk of him getting homeschooled and stuff, to avoid problems because of how well known he is at school.
By the way, we don't go to the same school anymore, that was in middle school.
I do see Hayes Greyer around town and at the mall in my hometown though, if that counts for something!