Former pupil's story about college bar (8)
I believe the answer is:
obstacle
'bar' is the definition.
(I've seen this before)
'former pupil's story about college' is the wordplay.
'former pupil's' becomes 'OB's' (abbreviation for 'Old Boy').
'story' becomes 'tale' (synonyms).
'about' means one lot of letters goes inside another.
'college' becomes 'c'.
'tale' placed around 'c' is 'tacle'.
'obs'+'tacle'='OBSTACLE'
(Other definitions for obstacle that I've seen before include "It obstructs or hinders" , "The problem" , "Barrier or deterrent" , "Blockage, hindrance" , "race" .)