Journalist's robust idea abridged when broadcast (9)
I believe the answer is:
subeditor
'journalist's' is the definition.
(I've seen this before)
'robust idea abridged when broadcast' is the wordplay.
'abridged' means to remove the last letter.
'when broadcast' indicates anagramming the letters (broadcast can mean disperse or spread).
'robust'+'idea'='robustidea'
'robustidea' with its final letter taken away is 'robustide'.
'robustide' anagrammed gives 'SUBEDITOR'.
(Other definitions for subeditor that I've seen before include "One proof-reads writers' copy" , "Employee on paper" , "Newspaperman" , "Observer employee?" , "News employee" .)