Already some great advice here, just wanted to add something:
When I read your sentences like
because he doesn't do anything slow
So the next time I said, "tunnel" he raced through
it sounds to me like he is enjoying agility itself but just has some problems when it comes to the volume of you commands/praise.
I would just start agility and try to speak resp. give commands as quietly and "unexcitedly" as possible. If he loves to race through the tunnel, just let him without praising him verbally when he gets out, just throw the cheese so he can chase after it and pick it up (maybe think about using a clicker?).
As soon as he gets what it's all about and with your training steps you are doing to get him used to louder things outside of agility (personally I would also train something like this while blood tracking, if that's somehow possible) he will become more and more confident and will be able to deal with commands, praises etc. better.
The instructor said he needs to be more bouncy and excited about what we are doing
See, I wouldn't say that. With some dogs, they just have to learn to enjoy it (as silly as it sounds
) but your dog seems to be one of them. Just let him do his thing first, keep quiet in the beginning and increase the volume when he gets a little more self-confident.
Just my two cents!