8 Month Old That Gets Overly Excited.

It sounds pretty normal to me =) babies just get really excited at the world around them at this age! Babies learn by touch, taste, sound, etc. so that's how they explore their world.
You can definitely teach a baby this young! I started teaching my children as soon as they could scoot themselves around on the floor! When he grabs hair or pinches, tell him simply "no, be gentle" and gently remove his hand. When he bites, say "ouch! that hurts mama!" and tap his cheek very lightly to get him to stop clamping down. The key is that it takes 100% consistency to teach a baby. Repetition is how they learn. You may have to do it 30x in a row, but take it from me, he WILL learn and it will be so much nicer for everyone involved once your hard work pays off!
Interaction with other kids is a great way to have new situations pop up where you can teach a lesson. I would start out with playdates with moms you know who will be more understanding to the situation. Once he learns to be more gentle, then you can take him to classes like Gymboree, library story time, etc.
Also, you could get a baby doll to help teach him to be gentle. Teach him to kiss and hug the baby. Teach him to pat skin and hair gently. This is a great opportunity to introduce new language ("gentle", "soft", "kiss", etc.)
Also, when babies bite, it's usually a sign that they're teething. Try giving him some orajel to ease the pain and teething rings, teething biscuits, even just a wet washcloth to chew on.

At 8 months I would take this as a "teachable moment" and tell him - no touch, or gentle hands. I would give him a few tries, and if he continues (which he probably will) then remove him from being so close to the kiddos.

He probably won't obey your statements at this point, but if it were me I would definitely follow through with showing and telling him right from wrong. Even if he can't process it, you are starting to show him acceptable behavior!

I've never been to gymoboree, but at 8 months I'm not sure how much interaction he will have with the other babies. I would try it, you never know, and he has to learn!

So many babies do love other "tinies," and do not have any idea that they are too excited or physical. The more opportunities to learn, the better. I agree that you should be right with him as he makes contact, guiding his hand in gentle touch, using the words easy, soft and gentle.

My grandson was much like this – very, very social. He did have a big, patient yellow lab to torment with all his love, and on whom we endlessly practiced the soft approach. It just takes time and plenty of repetition. For months.

With a lot of nephews n nieces, I do know that some babies l-o-v-e other babies. Some of them are always poking eyes, pinching cheeks, etc etc. He could just be an aggressive baby. Some of them really love them, smiling, kissing, etc. One of my nephews was a biter, a niece loves to pull hair (and really has fun doing it), and another nephew just loved to hug n kiss other babies, even wants to hold them already. :p

I not sure this is something that can really be "corrected", but then again, I don't have the whole 24-hour experience with babies yet. Sorry if it didn't help!

Totally normal. Mine does it too!