Being promoted from 8th grade to 9th grade is expected in my family and not really worthy of a celebration, IMO.
I see this as a kind of trend where kids celebrate graduating from pre-k, k, 5th grade ect...Just like every kid gets a trophy kind of thing, which I, personally, do not agree with, either. I want their HS and college graduations to be THE BIG DEAL and not, ho hum, for them.
These are things I expect from my children, just as I expect all A & B's on their report cards.
That being said, if you want to acknowledge it, I suppose a t-shirt or sweatshirt from the new high school would be neat.