This is a GREAT time to visit OC. The ocean is still warm, the breeze is cool and most businesses are still open 7 days a week. The crowds are way down and there's little to no wait for a meal. I know from experience because my mom and I have visited this time of year for the last 2 decades to celebrate our September birthdays!
I have the perfect place for you, Beach Plaza Hotel at 1301 Atlantic Avenue, OC, MD 21842. You can reach them at 410.289.9121 or
http://www.beachplazaoc.com/.
They are right on the boards and the ocean, with quiet, quaint rooms. Beach Plaza has a wonderful porch with inviting rockers so you can grab a fabulous mixed drink at the bar and grab a rocker to people watch while enjoying the ocean breeze. And you're in for a treat if you venture into Bombora, the on site restaurant. All I can say is how pleasing Chef Arturo's creations are to one's palette. Visit
http://www.bomboraoc.com/ for more information.
Off site you are a short walk to other food and drink venues. You could basically park to check in and leave your vehicle there the entire visit. (Saving gas!) If you choose not to walk you can step off the porch and right onto a tram car that will take visitors from one end of the boards to the other.
Have a great time! And Happy Birthday!