OP, I feel for you. Many of us have been through the mill with extremely bright, headstrong sons who don’t get that yes, they DO have to sweat the details, and everything cannot always be pulled out at the last minute. It starts years before the college admissions process. It can be monumentally frustrating to see them messing up, and monumentally difficult to judge when to step in and when to let things fall as they may. BTDT myself.
But your S has some really great choices, even if he doesn’t get in off the waitlists, so although he has suffered a blow to his pride, he will be fine. And, believe it or not, he WILL mature. 
It will probably take several years, but eventually he will get his act together and take charge of himself. BTDT also.