I took my boy every day to a local park when he was a pup. Lots of kids running around, v exciting for him. I instructed the kids that when Snowie raced up to them, to fold their arms and turn their back to him and stand still, not run away. It was v effective. Stopped him jumping up on them. I got the kids to practice folding their arms and turning their backs and standing confidently. They felt v empowered by this action. I must confess he did down two kids when they were running, he bounded up behind and jumped on their backs. No harm done thankfully, but terribly embarrassing. Thankfully we were all local and no bad feelings.
When my previous love, Max, was about 6 months old he did the jumping on everyone thing. Seems he couldn't contain the excitement, no matter how calm the visitor was. My solution was to leash him if someone came over, and tether him to a piece of heavy furniture. Try as he might, he couldn't jump on someone he couldn't get to. The phase did pass, but not without alot of lessons. I remember one lady who came over who I mistakenly thought was a fellow dog person. Max knocked her down. Fortunately, she landed in the easy chair! He meant no harm, but he was already a big dog. I'm going to have to remember this for Moose. And buy another leash (one is never enough - used to have them all over the house).
Im late to this thread so mostly skim read it but havent seen this mentioned - look into clicker training. You can click for calm behaviour. I did this with Penny as she went through a phase of lunging for everything on walks and we taught her the clicker, it was brilliant. You do need to research and make sure youre using it correctly though as i see far too many people using it to try and get the dogs attention when its meant to be a cue that theyve performed the desired behaviour and are about to receive a treat. Consistency is key and you will get there in the end. The adolescent months are hard and when i worked in rescue 6-12 months was a very common age for puppies to be given up due to owners that couldnt cope. When you get through the other side it will all be worth it though.
