Cricketer initially happy about the headgear (6,3)
I believe the answer is:
bowler hat
'headgear' is the definition.
(bowler hat is a kind of headgear)
'cricketer initially happy about the' is the wordplay.
'cricketer' becomes 'bowler' (bowler is a kind of cricketer).
'initially' suggests taking the first letters.
The initial letters of 'happy about the' is 'hat'.
'bowler'+'hat'='BOWLER HAT'
(Other definitions for bowler hat that I've seen before include "weapon in a Bond film?" , "traditional topping" , "what retired officers used to take on" , "Domed headgear" , "lid" .)