Capital sum for the college chief (9)
I believe the answer is:
principal
This clue might be a double definition.
'capital sum' is the first definition.
'college chief' is the second definition.
'principal' can be an answer for 'chief' (I've seen this before). I am not sure about the 'college' bit.
'for the' is the link.
Can you help me to learn more?
(Other definitions for principal that I've seen before include "Key" , "Star" , "Stop" , "property" , "Chief, main" .)