I don't think a kid would be intentionally optimizing anything in this situation. So if you mean that creativity is not only a tool to be used conciously, I agree.

I just mean I think it's difficult to argue that anything we humans do can be viewed as anything else but problem solving.

So in the case of the kid there might be millions of direct reasons (e.g., boredom > want to solve that), but I think it would still be possible to map any of them to some form of problem > effect or cause > effect relationship. Nothing happens without a reason (without religious connotation).