Btw, at Fenzi what course did you take & did you do, bronze, silver, or gold? Since he's 9 months, was unsure which course to try if I do. Control with the crazy canine sounds fitting. 8/
I did Shade's fundamentals courses, Drives and Control 1 and Drives and Control 2. I've only done Bronze level since I'm okay learning on my own. It would definitely be valuable to do Gold level and get feedback, especially if you don't want to spend the time wading through all the other posts to find advice that might apply to your dog. I just didn't want to pay that much, haha. And I don't think Silver is worth paying for since you don't get feedback on your own dog, and there are lurker groups on Facebook where you can share videos and have other students try to help.
There is also an Impulse Control for Agility Dogs class by Nancy Gagliardi but I haven't taken that one yet. You can always email the instructors to see if they think their class would help you or recommend a different one.
Arousal and agility can be super tough to balance. Because we do want them aroused and excited while doing agility! It can also be tough to battle because we are creating a conditioned emotional response to agility. Essentially the dogs are being classically conditioned to be excited and aroused around agility things. And with classical conditioning, the dog's response is rather involuntary and harder to change. Especially if we actually want them excited in the first place.
Just some brief blah blah about the science of arousal and overexcitement around agility.
For now I think you could just work on being very consistent that quiet = play, whining/barking = back to the crate or waiting area or whatever. Lots of work on focus and eye contact for lots of rewards.
Try to find other areas where you can practice this concept. Like with my dog, swimming gets him to that same over-aroused squealy whiny state so it's just another opportunity to practice quiet and control = swim, being crazy = no swim. Things like that.