At the Koala Park Sanctuary in West Pennant Hills you can hold koalas and get a photo with them. They're also fed multiple times a day. I haven't been there yet but I've been meaning to go for a while.
There are so many places to see koalas in and around Sydney! I have visited Taronga Zoo and the Australian Walkabout Wildlife Park in Calga and both were amazing options. While Taronga Zoo is more expensive, the Australian Walkabout Wildlife Park may be more difficult to travel too. Both options however provide the opportunity to view koalas, along with a whole variety of other animals.