I've been following your post and I very much feel for you. We are in a similar boat, however my son is not as active. We also have a younger child as well. Once your younger child is a bit older, you won't be in such fear for their safety. As for ADHD, I have been reading a lot about it and you might want to read about how there are two basic types, one can have a combo of the two or predominitately one type. My son can focus for hours at a time so I always assumed he couldn't have ADHD but then I read about the impulsivity-hyperactivity type. His behavior goes in waves. For two months at a time during a cognitive leap period, his behavior is all consuming for us and our lives are captive to it. Then we'll get a week or two week break of fairly calm and compliant behavior.
I hope you can get a professional who really listens and sees him in the whole picture. I, too, was waiting through the 2's, 3s....and now getting close to 4, I know that so much of this is who he is.
We called the school district and they agreed to do a full eval so that will be done in a few months. I have had a very hard time getting any feedback from our pediatrician who just sees a very cognitively advanced boy, adorably having adult-like conversation with her. I feel grateful that the school psychologist is willing to do an evaluation.
I thought I read somewhere that you said someone is responding to you as if your son must be "some hardened criminal". Don't worry about people on these forums judging you, you are in good company here. So many of us have gone through what you are now and or, in my case, going through something very similar. I have recieved more help in these forum than anywhere else. I am always amazed at how willing people are in helping me and I am grateful.