Sorry Cheetah, only saw your post after I posted mine.
Our 9 years olds will accompany us to Kruger this winter again. Purely for two reasons. It is cooler and mosquitoes are less frequently encountered. We scale down our personal preferences in Kruger when they are along. As much as they enjoy nature, we cannot expect them to sit in a car all day long and look for birds and animals. They get bored and tired after a while and it is unfair to force something upon them. All it does in the end is make them dislike the experience.
You have to keep them entertained almost all the time.
We always play a game in the car to see who spots the best and most animals/birds. Around the fire at night we have a prize giving ceremony.
They also have games in the car, Nintendo 3DS, a DVD player and other toys to keep them occupied during lean viewing times.
Out of the camp early with a breakfast at a picnic spot and back in camp before midday is the order of the day. Then they can run around and swim or just relax at camp till our late afternoon drive again.
For those who risk taking younger ones to Kruger. I have found that Berg-n-Dal is a nice camp for them. There used to be a little Jungle Gym near the reception. Unfortunately I am not sure if it is still there. The shallow pool is also safe and very popular.
Camps like Skukuza and Letaba are also great because of their museums. Some camps like Skukuza also still shows films at night.
Kids love toys and shopping. Most of the big camps have lovely shops where they can spend some time at.
Satara and Lower Sabie for instance have nice big lawns with lots of shade where you could let your little rascal run off some energy away from others who the lovely noise of child laughter might annoy.
Teach them to be quiet at bird hides. Most of the old farts spend there time in their and I in particular have had a nasty incident at the Sweni hide one year after a lady made a comment about silence after my daughter had asked a bird related question.
Get them their own cameras as well and encourage them to use it. They at times take the most entertaining photos!