Psi,
Please don't take offense to this, because I really mean no harm, but it sounds like maybe you need to educate your guests a little. Please remember that Psi is only a puppy and some will act like this no matter how much training they have. I don't think that the solution to your problem is to put him away whenever guests come over, I think that in doing this, you are just pushing the bigger problem "under the carpet". My girl, Nedra, is 11 months old and exactly the same way, but I know that the only way that we are going to stop the behavior is to desensitize her to it by intentionally keeping her out. When she gets a little too rowdy, I grab her collar and put her in a sit/stay (make him sit and do not have the guests pet him until he stops wiggling. If they approach and he starts again, have them turn around and walk away. When he stops wiggling, then they can go up and pet him). When she sits and stays, my guests go over and pet her. If her butt leaves the floor, they stop petting her immediately, stand up, and walk away. She is catching on slowly but surely, but I do have to say that it is getting much better with age. I know that your guests that don't particularly like dogs won't be up for helping you train your dog, but guests that are dog lovers generally have no problem helping out with this.
If certain guests are afraid of him, set them up for a game (children generally love this). When there is food around, I'd be willing to bet that Psi doesn't act like a psycho-dog. Nedra suddenly turns into the perfect dog when the treats come out. Have the children work with him with treats, by doing sit, down and stay exercises. This is the best way to get them "warmed" up to each other and to show the kids that he really isn't a mean dog.
And there is never such a thing as too much training. It is especially important to keep them in obedience classes at this stage. You will find that the actual organized obedience classes give you the opportunity to work with him around 8 or 9 different dogs and their owners ( <-- strangers) in a controlled environment. I went into our class with "the more dogs the better" attitude because Nedra is a fool around other dogs. She just wants to play so bad... :rolleyes:
Good luck! Keep us posted on his progress!