It’s a couple of years since I visited the Rock, but I would recommend that you do go in as soon as it opens because as others have said it gets very busy by about 10am. This is fine if you like people pictures.
There is a ruined Abbey about half a mile away which will also provide photo opportunities, and a vista of the Rock. There is a footpath from near the Rock entrance, or you can drive there.
As you come out of the car park there is a row of cottages/shops on the right, one of which is/was a good café with a pleasant garden opposite.
Apart from that enjoy the day, and do not, whatever you do, save film.