..The issue is that even after he is recruited he still needs to play his senior year right? This is the idea behind the move to a new school. As parents, we are trying to make the best decision for his senior year overall while recognizing the importance of baseball in his future plans.
I'm a bit reluctant to offer parenting advice but you specifically asked, so...
There are so many things (beyond baseball) to consider before moving a kid to a different school, particularly his senior year and particularly with sports as a major factor in the decision. Please think them through thoroughly. Only the parents and son will have enough info and insight to make a properly measured decision. That said, I think it is good to ask here. Some can offer up specific scenarios to consider, such as what Coach2709 provided. Is it legal? Would he forfeit athletic eligibility? Does the son want to move? What logistics issues will this cause? Where is the stronger friend network? Other activities? Other adjustments? Other kids? Academic comparisons... the list goes on. You can also search the forums here for more discussions on the topic.
I think you are seeing enough signs to know that playing HS ball his senior year is not necessarily critical to playing at the college level. I also think JH said it best about using this as a learning opportunity for your son to take responsibility for his actions (ironically, JH is one of the only posters on this thread who is not a parent). This may be one of the last chances for you as parents to send the right message and teach him in that regard. I think, even as important as baseball may seem right now, this is far more important.
If your son tries to do the right thing (take the high road and make amends with the coach and make a sincere effort to adjust his behavior), I believe it will eventually work out for the best. Even if the coach does not respond to his efforts, there are other ways to get the necessary work in to continue to hone his baseball skills.
As a HS coach, I get some kids with stellar character, several with typical teen maturity challenges, some with issues beyond the norm, etc. I think the most rewarding interactions I have are when the kids with the typical maturity challenges show efforts to break through and become respectable young men (and teammates). I certainly would welcome hearing from a player who wishes to do so, regardless of any past issues.