I recommend the reef,playing area on 1st floor of Royal Plaza.There is a special playing area for kids younger than 2 years old.He can make different activities with one visit only(playing ,drawing ..)he will be able to play with other kids having the same age.
Bennigans is good if you want it as a dinner or lunch.It has a spacious and clean playing area too .
you can take him to the Zoo, or Al-Dosary Farm, Circus World at Landmark is also fun for them, Ceramic cafe at the mall is great also, try Jungle zone at Hayat Plaza, and playing area at Royal Plaza is better for his age, they have cute soft play area, try also sending him to nursery they could be of great fun for him...
If you wanna make his birthday try Illy france cafe they have an upper birthday hall for kids, so cute.
The new fun land opened at Villagio is so nice also
Jungle Zone at Hyatt Plaza do organized kids parties of all ages
Try Funland at Centrepoint