Put off over this compiler's limit (9)
I believe the answer is:
determine
'limit' is the definition.
(I know that limit is a more specific form of choose)
'put off over this compiler's' is the wordplay.
'put off' becomes 'deter' (both can mean to discourage).
'over' says to put letters next to each other (in a down clue, some letters go over others).
'this compiler's' becomes 'mine' (belonging to the crossword compiler).
'deter'+'mine'='DETERMINE'
(Other definitions for determine that I've seen before include "Choose" , "resolve" , "Dictate" , "Learn" , "Ascertain by research or calculation" .)