Welcome to the site, BBdad.
You said... "We know the coach does not like him, he said so and its the same coach this year."
Based on the abundance of other information you provided, it is likely not his playing ability that the coach doesn't like. So, what is it? I don't know your son's situation or if any of what I am about to share applies. But in my experience, your son is probably very aware of what the issues are. And, those issues are very likely to be the same that cause the next coach to not like him as well. And, assuming I am the least bit on the right track, he needs to face up to those issues and fix them. He needs to share with the coach that he recognizes them and is addressing them and then he needs to do it.
I head up a decent program and coach V. I oversee the entire program before we split off. We have a handful of juniors that are still playing JV this year. Generally, it is not due to their lack of talent. Last night, we took advantage of a rain night and I conducted a hitting discussion for the JV group so that they all know the program way and so that they have a clear path toward continued improvement. Toward the end of the discussion, I had to kick two players out of the meeting. They were two of the juniors. It was no real surprise. They don't lack talent. They were doing what they do that dictates why they are still on JV. They comply just enough to stay in the program but don't care sufficiently to address the issues that prevent them from being a part of the next level in the program.
Again, I have no idea how much of this applies to your son.
I also see that you have been involved in coaching previously and I see that you have quite a depth of statistical info on your son as well as exactly how his numbers compare to others on the team/in the program. I suspect this won't go over well but my suggestion is that you let go of this, at least to a large extent. The way you are using the comp numbers is not healthy or productive for your son. Don't look for reasons he should be "in". HE should be looking for reasons he is "out" and working toward eliminating those. He should be working toward being the player the coach wants in the lineup, on the field and in the dugout as a teammate and he should have the goal of leaving no doubt with all three... regardless of who the coach is.
You found a site that can be a treasure trove of information and direction for you both. I hope my "less than rosy" message doesn't scare you away from using it to the fullest.