Maybe he is just bored. You need to do different activities with him. At this age they love music, dancing, playing music instruments(maracas. xilophone, etc.) Finger painting, climbing, etc. That is what they do in preschool, the difference is that in school they gt to be with other children and that makes a whole lot of difference. Maybe you can put in school half days. He will love it, at first it will be touph if he is notused to being without you but he will get used to it by the 3rd or 4th day. You will both be fine..
With regards to ADHD, your son sounds like a perfect 2 year old. I have 2 boys one 18 and the other 7 and a daughter who is 15 months old. At two children are discovering so many new things they can do, and they are big explores. Don't let anyone label him so soon. he is still too young. If by the age of three he is not speaking as he should or doing things that he is supposed to do then you need to get worried.
I do have one of my boys who is ADD(he is not hyper) and he was diagnosed ADD at school age about 6. When he was three he was tested because he did not speak in sentences yet so they discovered that he had learning problems, but at 18 he is just a very normal teenager, who learned to deal with his disabilities, you couldn't tell if you spoke with him that he had all of these problems growing up. When they discovered his ADD they gave him meds which made him feel worst, stomach aches, nervousness and mood swings, so I took him of meds and learned as much as I could about it and help him self help himself. Also his school was very helpful all of the time. But I never went back to his meds. As he grew older I gave him genko biloba and he still takes it before he goes to school in the morning. That seemed to help a whole lot.
Any ways your two year old seem to be just a two year old who is discovering a new world that is opening around him, for what I have experienced with my three children. I wouldn't worry for now.