Covering spinner for one that's heading off (6,3)
I believe the answer is:
bowler hat
'covering' is the definition.
(bowler hat is a kind of covering)
'spinner for one that's heading off' is the wordplay.
'spinner for one' becomes 'bowler' (spinner is a type of cricket bowler).
'heading off' means to remove the first letter.
'that' with its initial letter removed is 'hat'.
'bowler'+'hat'='BOWLER HAT'
(Other definitions for bowler hat that I've seen before include "what retired officers used to take on" , "lid" , "Headgear of stiff felt" , "Headgear with round crown" , "Domed headgear" .)