Hi K.!
The teacher is very important, what is that 5th or 6th grade? The middle years are often a very big struggle for kids with ADHD, and you will probably run up against teachers who doubt the diagnosis, or think that smart kids who have ADHD struggle with "attitude" and "choice" instead of a biological chronic illness; especially when the IEP modification or accomodation is difficult for them to accomplish (I have noticed a strong corelation between those two items...)
Medication is an issues for kids of the age group too, but don't give up. They are changing and their feelings about themselves are so volitile when they struggle in school, and they will need careful and skillful monitoring and a willingness to try new dosages and medications. I urge you to not fall prey to the anti-med brigade, diet, supplements and exercise are great for health, but they will not help him with his ADHD, and neither will removing sugar, dye, or preservatives, etc.
We did ask for a behavior plan at school, even though our child did fine with teachers who did the right things without it, once they run up against a teacher who does not have the proper class structure or personal compasion to help a child with ADHD thrive, the problems may linger even after you get them into the right setting.
The plan should protect your son, and let me say that as an educational advocate for many years, I have seen a vast difference in the way boys and girls are treated when it comes to behavior. It is not fair, but being a boy puts him at some risk, and schools traditionally crack down harder on boys than girls (for the same behaviors) and eventually, the possibilty exists that someone will call the police. If you have never thought of this, trust me, it happens all the time for very small behavior and the behavior plan can protect your son by spelling out the behaviors he has, and the specific concequences for those behaviors that are going to be used, and you have a leg to stand on if the school escalated the concequence without notifying you of thier plans.
You are doing the right thing by getting counseling, it can help him sort out how he feels right now, and may make the transistion to a better year next year run more smoothly. Cognitive behavioral therapy and medication work very well together.
If you do not have a leg of his evaluation that includes a full work up about his executive functioning skills, or lack there of, you should ask the school to do this, and get a private one that you control. The middle years are difficlut for kids with ADHD, not because they change, but the expectations of them change and suddenly they are expected to know how to use thier time well and turn in thier own assignments. Teachers assume that our kids will pick this up by indirect teaching and natural concequences, but most of them won't. We ended up hiring a tutor who stayed after school with our daughter and they did the homework together, not for academic reasons, but to be able to find all the papers, books, and intructions and then teach her to organize it, pace herself, and turn in the assingments when she was done. Most kids with ADHD will need some very detailed help in this area, and what they get in the classroom is not nearly enough.
Or biggest heartache was seeing a child go from doing well, to one who was frustrated and angry, almost overnight. The reaction is very predictable, they rebel. It is sad, but they tend to be beat up with thier own sucess, I am sure that you have had a teacher doubt the diagnosis, or remove a core element because your son had a sucessful try at something. "He turned in the social studies last week, so that means that he can do it if he chooses too, so I don't see why we have to help him with that, it is JUST his attitude..." this crushes their spirt. Any really smart kid would quit being sucessful even when they can if they know that they will be beat up about it later!
Good luck!
M.