I think you should attend. It is a great opportunity for your son to meet some people (both current students and administrators) and get some of his questions asked about classes, majors, dorms, meal plans, activities, sports, local transportation and banking. There is a lot you can learn that will help you hit the ground running in August.
We did this at several schools last Spring and it was very helpful. Being ED, I realize you do not face the same choices and options we did juggling multiple EA schools. but spending a night in the dorms with a current student and following them to class is really useful for your child.
Many schools also have “Send-off parties” for incoming freshmen in late summer, as well as more informal summer events sponsored by alumni groups. Those are also highly recommended and really useful as you will meet current students, recent grads, older alums, and current parents. Your son will benefit and so will you.
Eight hours in the car is not too bad and will help you scope logistics for August move-in. It can cost a little money and a vacation day or two, but it is very worthwhile to your son to know what is coming. You won’t regret it.
Good luck!