My DS was a good 11mths before he took more than a few sips of water from a sippy cup. This is quite normal though - it just takes time. Most babies are about 12 mths before they are capable of drinking a full milk feed from a cup - then milk comes out really fast and makes them very windy if they gulp too much.
DD has managed a cup well from about 6 mths. It makes me laugh to see her with it as I remember J was so useless. She holds and tips herself - I had to do it for J for AGES. Actually she is obssessed with cups and crawls around baby groups trying to drink everyone elses drink
.
I would put money on her getting the hang earlier simply because DS still uses a sippy a lot of the time and she has been able to copy him.
After a lot of trial and error DS took a tommee tippee first cup (and he still uses that now when we use one at 2.5). DD can use a tommee tippee as well, but she tends to gulp and choke, so we use a new one called a tommee tippee 'tip it up'. It is non spill but only needs VERY light lip pressure to work. The fluid comes out a bit slower so she doesn't gulp so much.
Don't worry about this at all yet - your LO will get it in time.