“King James” isn’t about LeBron James. The NBA superstar isn’t a character in the play, but his presence looms large. This is a story about the fan experience and how sports bring people together. It centers specifically on LeBron’s impact and influence on two sports fans, played by Glenn Davis, who appeared in “Bengal Tiger at the Baghdad Zoo” on Broadway, and Chris Perfetti, who can currently be seen as Jacob in ABC’s hit comedy “Abbott Elementary.”