What everyone else has said...
Remember that protein powder is nothing more than processed food. Think about it as the same as sugar in that sugar is just highly processed grains or vegetables. Protein, most commonly whey, is just processed milk (or other protein base eg. eggs).
Creatine is simply an amino acid. Amino acids are the building blocks of proteins. Your body can create it and it is found in meats. It is one of the few supplements that have been scientifically proven to help. There are some known possible negative side affects of creatine. In my opinion, they are a very low risk. However, for a child, I would not recommend. Additionally, as long as he isn't taking more that 10g per day, if you caught him taking it I wouldn't flip out. It can be a little taxing on the kidneys and liver. It would be a good opportunity to discuss the unknown long term effects and general supplementation and that in fact, by taking them he is a human guinea pig.
Both are completely unnecessary if your child is eating enough of a well balanced diet. Kids will be kids and if all his friends are taking protein (and maybe creatine), I would have a discussion with him telling him it is nothing but food and don't believe all they hype. Then I'd buy him some Optimum Nutrition Gold Whey and let him have at it. It is a good, low fat, high protein, low sugar food.
Class of '94