My first daughter was a lunatic when she was learning to walk. You wouldn't believe the bumps and bruises she had. My mother kept telling me to put ice on everything; but she'd have been immersed! Anyway, I asked the Dr when did I need to worry about her hitting her head and he said "if she loses consciousness" !!!!! I have to tell you I really respect my Dr but this surprised me. But if you think about it you can't chase them everytime they run and they do need to learn cause and effect. He will learn to fall on his bottom in no time, really. My daughters big problem was putting on the breaks. But if you can clear everything out, which I bet you already have, that is about the best you can do.
I am going through this again with my second daughter. She was a super early walker, completely from squatting she could do it on her own at 11 months. She is now almost 13 months but you should see the knot she has on her head. It makes my stomach hurt. I had to take her to the Dr with it like that for her 1 year shots and the Drs and nurses just go "ah, learning to walk can hurt huh?" No one even asked me the source of her bump, that surprised me I was all ready with an explanation! None needed.
Anyway, I think you are doing great. Just do what you can but he needs to get a few bumps so he can figure this out.
Take care.
H.