My almost-8-month old prefers to self feed too. I do manage to get food into him, but I just fill the spoon up and give it to him, then he puts it in his own mouth. He's eating puffs and Cheerios now too. I've been debating starting him on some other soft solids too. I think their ability to deal with solid food has less to do with teeth and more to do with readiness - remember that there are many 1-year-olds with only 2 teeth who manage all kinds of solid food fine - you just have to make sure it's soft enough to be mushed between the gums.
When I was doing some research for my own ds, I came upon some info about Baby-led Weaning - the idea that you can skip the feeding the baby thing altogether and have them start self-feeding at 6 months as long as you continue nursing on demand. Check it out:
I think I may start trying him with things like small pieces of soft avocado and small pieces of rips banana and see how he does.