There's nothing left after half nine (3)
I believe the answer is:
nil
'there's nothing' is the definition.
(nil means a score of zero in football)
'left after half nine' is the wordplay.
'left' becomes 'l' (common abbreviation).
'after' is a charade indicator (letters next to each other).
'half' means to take half the letters.
'nine' cut in half is 'ni'.
'l' after 'ni' is 'NIL'.
(Other definitions for nil that I've seen before include "Nothing, zero" , "Latin zero" , "Non-existent" , "Nothing, no value" , "Score of nought" .)