Tramp's son turned out to be a player (9)
I believe the answer is:
sportsman
'a player' is the definition.
(I've seen this before)
'tramp's son turned out' is the wordplay.
'turned out' indicates an anagram (turn out can mean to organise).
'tramps'+'son'='trampsson'
'trampsson' anagrammed gives 'SPORTSMAN'.
'to be' is the link.
(Other definitions for sportsman that I've seen before include "Chap aiming for game" , "He engages in physical games" , "Eg, athlete" , "Rower perhaps" , "player" .)