The first thing to understand is that it will be up to the state of Washington as to whether or not they would be willing to accept his case for supervision or not. Your son will have to discuss these arrangements with his probation officer in Connecticut; if Washington says they won't accept him that is the end of it. He should also have to expect to have to register with Washington's sex offender registry list. These laws are established and exist in every state. Since your son was convicted of a sex offense he would be obligated to follow the laws of whatever state he resides in. The judge in Connecticut can't order another state to not enforce its' laws regarding registration. The only possibility, (and it is very thin), would be to hire an attorney to argue to the court in Washington that since the judge in Connecticut exempted him from registration that the court in Washington should defer to that determination; further, I don't think that any court in Washington will consider this request until the situation becomes a real situation. In otherwords, you can't get an attorney and present this scenario as a hypothetical to the court and try to get an order prior to the move. Also, remember that in many states the judge doesn't have the kind of discretion that the judge in Connecticut had. Absent that I believe your son will have to register in just about any state he would move to. You should contact the local bar association and get a referral for an experienced criminal law attorney in your area and make an appointment to discuss this situation with him or her.