I would say go for it. I didnt put my son on a sippy until he hit 1 year, but he did well with his bottle. I have a friend who put her son on a sippy at 6 months and he is doing great. Also I would assume she uses formula in it.... Good Luck
Sure! I think I started my son on a sippy cup at about 6-8 months. He got disinterested in the bottle, too. I think it was because the flow from the nipple was slower than with the cup. You could get some faster flow nipples, too. But hey, at least you'll know he won't be one of those kids that refuses to get rid of the bottle, so that's good! :-)
A sippy cup is fine to try. I've been using one with my daughter since she was a little over 5 months. There's one that is made for 4-12 months old. Take out the plastic/rubber insert and you'll have to tip it up for him. It would also be good to have a cloth handy for putting under their chin.