The age of the puppy is determined on the date of the show - so if the puppy is under 9 months, he must be in the 6-9 month class. I believe the AKC allows class changes for age in the puppy classes if the entry was done wrong and the puppy needs to be moved to the correct class.
I think you have answered your own question - the dog either fits the age requirement or it doesn't.
I have a puppy dog that is very "mature" for his age and will not be shown in puppy classes. He is just 9 months now and would fit right into a 12-18 class. However, I can't enter him in that class Instead, we entered him in Novice class for his first weekend and will be showing him in American Bred until he is a year old. Sometimes a big, mature pup just looks out of place in a class with its age group.
You could, by why would you want to? Any wins or awards would be only revoked later. I was actually moved up from 2nd place to 1st place, (by mail a few weeks later) because the bitch in my class belonged in the 12-18 class, and was ineligible for the placement in 9-12. What if she had gone WB, and had that win revoked? That would be a horrible feeling for sure.
That has happened (quite a few times) and how do you think the winner of 2nd behind the DQd WD or WB feels knowing they should have had a shot at WD/WB?
Pretty crummy...
The age classes are just that - for the ACTUAL age of the dog, not what class you think the dog fits in. If you enter the dog in a class he doesn't qualify for - by AGE - then any awards will be taken away.
Why are you even wanting to enter an 8-month old in another class? If he's too big to fit into the class (your opinion), enter him in Bred-By (if you bred and own him) or Am-Bred instead.
In all the years I showed, I have only been moved up from reserve to winners once. It was precisely for the reason we are discussing. The first place 12-18 dog was winners and my dog went second in the class and RWD. The dog was over 18 months by a few days and the win was disallowed, giving my dog an extra point. Read the rules for each class and only enter dogs that meet the regulations.
I have 2 pups, both within a few weeks of each other in age and both will belong in the 6 - 9 class in an upcoming show. I just wanted to be able to handle them both. One is more mature, and would be fine in 9 - 12 (if it were legal). I think novice is too big of a jump. Not that I care much about winning at this point, as I just want to get them out, but I don't want her to look too out of place.
I was in that position last year. I just put one of them in bred by. We looked a little out of place, but she got her experience in the ring. That's all I really want with a pup anyway.