but your thinking is on the right track. Having your son show up on time for the hearing, with parent supervision, dressed neatly and prepared to explain what he has learned from the experience and how he is prepared to be a safer driver could reduce punishment to a warning or suspended sentence.
I've even had the cop show up at traffic court and when she saw that I was there and looked professional, she chatted with the prosecutor who told the judge the cop didn't remember the specifics and requested the case be dismissed.
Showing up, acting like reasonable citizens, accepting a teaching moment, and not causing the court trouble or being antagonistic to the cop is likely to go a long way.