You really do not need to declaw the kitten but at least trim down its nails so it won't hurt your son when it accidentally scratches him. Cats tend to do that when they feel so happy and excited while playing. They are very playful animals. When you see that their tails are totally erect, that means they are so eager to play. Therefore, do not let them start playing when you know the nails are really sharp and long.
One effective way to calm them down from time to time (when they start to become too hyper while playing) is also to give them treats in between. The time it takes them to much and then shallow the treat would give them time to slow down and avoid scratching your son.
