Driver might go through these short tee positions following golf ace (9)

'driver might go through' is the definition.
(someone might drive a car through gateposts)

'these short tee positions following golf ace' is the wordplay.
'these short' means to remove the last letter.
'positions' becomes 'posts' ('post' can be a synonym of 'position').
'following' is a charade indicator (letters next to each other).
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'ace' becomes 'a'.
'tee' with its last letter removed is 'te'.
'te'+'posts'='teposts'
'g'+'a'='ga'
'teposts' put after 'ga' is 'GATEPOSTS'.