The best bet is to get here early. It's odd that they open up at 9am. Why not 7am or 8am. It's difficult if you have a 8 or 9-5 job. Maybe add some tvs too look at while in line. The line moves pretty quickly but again I'd suggest getting here early as the line will start outside. The Employees that I've encountered are helpful and nice.
Be aware some services are payable only via cash so check out the ncdmv website before visiting.