The main thing is to train EVERYONE to get down to his level to fuss him rather than him attempting to get to your level. Teach him to sit reliably on command and he receives no attention until he is sitting and you are down to him. If he disobeys and carries on jumping then turn your back with your arms crossed and completely blank him out. As soon as he stops then tell him again to sit and then fuss him at his level. Not easy as children will wave their arms about and run away so excite him even more. It is actually the children you will have to train.
If you have good timing another thing you can try is to bring your knee up as he jumps (this is better with a big dog) so that jumping up becomes uncomfortable. Dont say anything when you do it it but again praise and get down to him when he stays on the ground. DO NOT let children try this one, they could hurt him and are sure to confuse him.
Good luck with it, children and puppy training is a big job!