How solid is he on the "sit" command? There are multiple ways that people use to train the "off" command, and keep pups from biting and nipping fingers. For as many replies as you get, you will probably get that many suggestions. My best advice to you is to pick the one that you are most comfortable with training method/theory wise, and give it an honest shot. It can be tempting to try something new every day because jumpers can be frustrating!
My personal advice to you is to ensure you have a very solid sit command on your dog. Ignoring only works to an extent. You can ignore as long as the day is, but some dogs just don't give up. And if they do, the minute you pet them because you think they are calm, they grow pogo sticks for legs again. I am not and never will be a "postive only" theory person. If you ignore bad behavior like this, you are reinforcing the behavior by not correcting it, IMHO.
For pups, treat training isn't a bad thing. Work hard on the sit command. This, IMHO, is the key to jumping problems. The dog doesn't respect you, or your space, if there is no alternate command you have no control other than physically holding the dog away (which just makes them push harder towards you often times). If your dog has a solid "sit" (with an IMPLIED at least brief 'stay') you can get this under control. If the dog can't solidly sit at 8 months, you have more work to do on leash before off leash will begin.
When your pup jumps, immediately give a loud verbal command of "OFF", do not turn away (your are the leader, the leader does not turn away), and immediately issue the command to sit. One command, one time. Your dog heard you. Nothing more annoying than someone saying "sit, sit, sit, I said SIT, no...sit!" If your dog does not immediately sit, one hand on the collar, one on the butt (not back) and make them sit.
Verbally praise for the desired behavior (the sit) and repeat as necessary each time the dog gets up. If you are VERY consistant and firm, your dog will understand that you are not playing around, and he must sit when told to do so.
Biting/nipping - by 8 months, I will take their mouth in my hands and give a loud verbal command of "no." Redirecting with toys is great, and works on many dogs. But if your dog is not responding to this or you are in any way confused about how it works correctly, I'd work on getting the immediate mouthing under control before the dogs mouths the wrong person. By 8 months, I like them to understand their mouth is not to be placed on my body or anyone elses. It is the one thing I don't allow from day one, but by 8 months your pup has established this behavior and you will need to be a little firmer about correcting it.