My son learnt on the usual trainer kites between the age of 4-5, then an ozone Uno with an epic junior bar, so the throw is short and the lines were 15m ish, from 5-6, then the best thing I ever did was get him a cheap ozone cat 2012 6m with normal length lines. I'm not all that convinced with the Uno, is behaves weirdly in my mind. That being said it was important to teach him throw control, so maybe its a good option.
The ozone Alpha mentioned by DM with an ozone wakestyle bar might be good option. This bar already has a small throw, use a small chicken loop then eventually replace it with a wakestyle loop when and if ready like for my son.
What you are looking for is a kite that will stay in the air when the wind is light. The rebel 6m was a disaster and put him of for a fair while lol. Wouldn't stay in the air in light winds.
As a parent (and most will probably agree) its a gruelling venture, Take hours and hours and can really stretch the relationship with your child. Wasn't until he was about 8/9 when he could actually follow and apply instructions. So your child is probably ready.
I took on Puertz's little game where I would suddenly yell "punch out!". if my son didn't immediately do the actions to release his safety he wouldn't kite that day...made for interesting times at the dinner table.
I still do it, but the other day he pulled the middle finger instead! Funny little bugger...
