I remember how worried I was about my baby hurting herself when she started being mobile, so I will try to keep the humor down... seriously though, a helmet?!
You baby will be fine. You don't need to do anything for rugburn on his knees. It bothers us moms more than it bothers them. If you REALLY feel it's necessary put some babylegs on him... but my daughter was always more bothered by those than the red knees.
The glass table is a different story, personally I think that glass furniture and babies don't mix well (sharp edges, risk of breaking...) and I would get something different. However if you really LOVE your table, put foam around the edge. You can probably just get one of those scrunchie things and put a little extra padding in. They are not meant to be supersoft, just to take the edge of and reduce the risk of serious injury.
All in all, all toddlers will bonk their heads and scrape their knees. It's part of growing up. Your job is to babyproof your home to avoid any serious harm, but a few scrapes and bruises are nothing to worry about.
Good luck.