Cut off a story by upcoming beat journalist (9)
I believe the answer is:
alienated
'cut off' is the definition.
'a story by upcoming beat journalist' is the wordplay.
'story' becomes 'lie' (I've seen this before).
'by upcoming beat' becomes 'nat' (I can't explain this - if you can you should give a lot more credence to this answer).
'journalist' becomes 'ed' (short for editor).
'a'+'lie'+'nat'+'ed'='ALIENATED'
(Other definitions for alienated that I've seen before include "Estranged" , "divorced" , "disaffected" , "put off" , "Date Liane (anag.)" .)