I also have a 9 year old and she loved Olu Deniz too!!
She wanted to visit the waterpark, but as we were only there for a week we didnt get around to going.
We are hoping to book up for 2 weeks next year, as she was so disappointed she didnt get to go!!
One thing to say, the sea at Olu Deniz is very rough!! My 9 year old got swept under a wave and this put her off going back to the beach for the rest of the holiday, but the lagoon is flat, with no waves, and she loved swimming there.
Personally I think Olu Deniz is perfect for any age group.
Try it and see, think you will love it!!
