Key choice about sport (3,6)
I believe the answer is:
ice hockey
'sport' is the definition.
(ice hockey is a kind of sport)
'key choice about' is the wordplay.
'about' is an anagram indicator.
'key'+'choice'='keychoice'
'keychoice' is an anagram of 'ICE-HOCKEY'.
(Other definitions for ice hockey that I've seen before include "Sport with puck" , "Team game played with long sticks" , "Violent sport, big in North America" , "Game played by skaters with a puck" .)