Apparently most of the rides, etc. at Stargate aren't operating. If you want to go there, probably worth a 'phone call first.
Pool party with an Hawaiian theme
Disco and jewellery making, etc. at home.
Some ideas off the top of my head:
Cafe Ceramique and the Bead Palace in Jumeirah do parties.
Atlantis Kids club can organise all inclusive parties on a number of themes.
My 9-year old DD just had a soccer party at ahdaaf football club behind Times Square.
Good luck!