We don't have synonyms for ballboy yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are bellboy, tallboy and callboy.
(n) :
Alternative spelling of ball boy. [(sports) A person, usually male, responsible for retrieving balls from the area of play, and returning them to the players.]
(n) :
Alternative spelling of ball boy. [(sports) A person, usually male, responsible for retrieving balls from the area of play, and returning them to the players.]