Country star Billy Dean plays Friday for a local crowd of new fans and old friends. He stood alone with an acoustic guitar on the small stage at his alma mater, Robert F. Munroe Day School — a place where the Quincy native wrote his first songs and played his first shows. Dean reminisced between pieces, sharing funny stories and lasting memories about his youth, his friends and his musical career that grew out of Gadsden County. Dean said Munroe hadn’t changed much — and he was happy it hadn’t. For a few moments before taking the stage, Dean sat by himself, looking pensive and waiting in the dark to greet a crowd that looked eager for the return of a hometown hero. “I’ll just go out and do my thing,” he said and stepped out into the spotlight.