Advice for ADHD child?

Bethany
I have a wonderful six year old, Damion, that has just started first grade. He is a very sweet kid and does well in school (good with spelling, reading, math) but he is displaying very obvious signs of ADHD. His teachers are getting very frustrated with him and all of my punishments seem to go nowhere with him. 
My husband and I have been curious about whether he has ADHD for a couple of years now, but his pediatrician said Damion can not be tested until he is seven. I can't even imagine trying to make it through the rest of first grade without some sort of help or diagnosis. 
Does anyone else have experience with a child that has this? Is medication going to be necessary? Are there any successful disciplinary actions I can take that will have a greater effect and get through to him? Should I put some sort of reward system into play? 
Any advice is greatly appreciated as I am lost and I feel bad about Damion being the "problem child" in his class. 😕💔