M.,
I am not a teacher, but an educational advocate for kids with disabilities. I sense that you have had a rough time already and may need some help. If I could offer you just a little bit of advice that could be helpful to you, it would be to learn some good solid advocacy skills. He is entering public schools, and there are some hurdles you need to jump here, and if you don't do them just right, you will be more angry than you seem right now. I get it, I really do. Take some deep breaths, because if you are ramping up for trouble, you will find it, and right now, I don't think you see where your trouble is really going to be yet. You will do much better if you can let go of what has happened so far and look in a different direction. It may be entirely possible that you will find people, including teachers, to be exactly what you expect them to be, so adjust your outlook and hope that you encounter some of the very best that public education has to offer. One thing I have found for sure is that even if you could have had a good experience, you won't if you go in expecting it to be bad. Chin up first...as hard as it is!
Something you need to know is that, number one, holding a child back is very bad for kids with special needs. It does not matter how the teachers will "feel" about it, the data about the effect on children is crystal clear. Go to www.wrightslaw.com and scroll down the left side of the page and read about retention. Schools provide intervention services based on grade, not age, so if you artificially elevate his age beyond grade, you will likely insure that he will never qualify for services. I know that the DP told you he "needs" it, but you have to jump the right hoops to qualify, and holding him back will not help on bit, and is not a successful special educational strategy or practice. Targeted intervention is, but first, he has to show both a qualifying disablity and an educational need. If you want to show need, with the kinds of issues you describe, don't hold him back.
"Behavior" can create an educational need. "Maturity" can create an educational need. "Attention" is an educationa need if your son has little of it. All of these things may cause him to be significantly behind his peers, but will trigger an evaluation by your school district, especially if your son is causing difficulty for the teacher. If you wait until he is 6 and behaves on the high side of 4, he will clear the bar, but you are comparing apples and oranges and he is still in great need of targeted intervention services while at the same time being in the general education classroom, but he willl likely not get them, and you will be fighting until he completly fails, and can thus show need. You don't want to get there.
Getting a one on one Aide is going to be very difficult because it is very expensive for the district. You need to be smart and negotiate well. Please understand that the DP may say so, but the school does not have to do what he says. The school only has to "consider" his evaluation and recomendations, and that is only if they decided to make a referal for him to special education. Technically, you can make the referal, but they can refuse. There are so many turns here, and you need to learn what to do. At the kindergarten level, you will be facing gatekeeping at the highest level. You need to learn as much as you can about this before you are faced with it. It is likely to make you very, very angry and will set you up for a very difficult path with this district far into the future, which will impact your son grately. The last thing you want is for the school to fight you on what they might have provided happily if you had kept your relationship with them on good terms. I am not saying that you don't stand up for your son, I am saying that you learn the skills that you need to do it on the schools playing feild, because right now, you really have little idea how to do that, which will lead to disaster.
Dive in at wrightslaw.com. Order the books, read the articles. Learn about how to start. You have an evaluation, but the school will need to do one too, and will likely tell you that they "must" try in class interventions prior to a referal for testing. You could start by writing a letter now asking for a referal for a special education evaluation because you suspect that he has a disablity. That is the languge, I know you know he does, but that is the language. You have to speak their langague. Learn about that at wrightslaw.
If you feel overwhelmed, check the yellow pages at wrightslaw for VA and find an advocate in your area. Do everything in writing. If it did not happen in writing, it never happened. Learn about something called Prior Written Notice, and ask for it when ever you ask for the school to do something. They must notifiy you in writing when ever they refuse or propsoe something, and they must list the data they used to make that decision. This is a very important tool that they will not want you to know about. Don't let them tell you that it is your invitation to an IEP meeting, learn exactly what it is and how to use it. The more you know, the less they will be tempted to get away with, but temper this with a good solid friendly relationship.
I know that this is a lot of information that you really did not ask for, but I have been there, and you need this information. You will be blind sided if you don't, and it is really easy to make critical mistakes early that just cannot be undone. Start by avoiding the first, and most distructive one, and do not hold your son back. Keep him at age-grade level and give him one full year more of targeted intervention and a chance at the special education services that he needs. Then, learn about being his advocate.
Let me know if I can help or you have questions.
M.