K.S.
Ah kids with extra energy are a challenge. At 4 its hard for them to get use to social cues. Just reinforcement reinforcement reinforcement. You need to help him learn to funnel that excitement to a less physical dangerouns to others. Like maybe doing jumping jacks or push ups or if he is outside he can run in circles. Just not to pick things up cause it might hurt the person you are excited to see. Also if he gets this excited now I'd really keep corn syrup away from him. And limit his sugar intake now. That way when he is in school you wont have this issue as much. Good luck