L.R.
Is there a specific reason why he must be in preschool at all this school year?
This isn't about a child who is already within the elementary school structure. He is four and in preschool -- which is not required by law where I Iive but is optional. It sounds as if he would benefit greatly from another year with no school at all, followed by preschool next year (yes, when he is five) and putting off kindergarten until after that year of preschool plus this year at home maturing and, if needed, being further evaluated.
You may be operating under the idea that you absolutely, positively must send him to kindergarten at five so he must have preschool right now, this year, but have you checked with the local public school system? I know many parents who did not start their kids in K at five but waited.
If your son is getting evaluations, what's really going on? Are preschool teachers and others telling you he is hyperactive?
If the old school complained about him, I'm not sure that putting him back there for three hours of pre-K (each day? Five days? Fewer?) would really help, and certainly it sounds like he does not belong in the more intensive program. I would really sit down with whoever is evaluating him and together consider having him stay home this year (if that is an option for you -- do you need preschool as babysitting due to work, for instance?) and then do a year of preschool after that, starting fall 2014, so that he is more mature and ready when he begins K in fall of 2015.
There is NO rush to start K for a child who is not mature enough, if maturity is the issue. And if there are other issues that require evaluation - there is still no rush to get into K at five. If you are worried about his being older than other K kids, please don't worry. He and they will not really know or care that he's older; he will start when he starts and they will be his peers in the classroom. And it is always better to be the older kid in a class, I think - you get to shine and be more confident, whereas the kids who are younger than the rest of the class (or less mature and less able to handle a classroom environment) often struggle hard.
You aren't very clear about his issues other than wiggliness. Be careful that his natural activity isn't labeled too quickly and consider that he may just not be ready even for preschool yet. I DO think that a good preschool for at least a year is really important to helping kids be ready for and succeed in kindergarten and beyond! But if he's not ready -- he's not ready.
If you do keep him home: Do a lot of activities where there are other kid around, structure, and other adults whom he must listen to and obey. For instance, do a lot of library story times where he has to sit and focus (or be removed and miss the fun); libraries and recreation departments do kids' craft events; recreation departments have lots of low-cost "mommy and me" classes in everything from tumbling (great for his energy) to kids' art and so on. Get him into limited but classroom-like settings frequently to help build up his ability to listen, pay attention and hold still over longer and longer periods gradually.