Power shown by writer -- shame page is missing (9)
I believe the answer is:
authority
'power' is the definition.
(authority is a kind of power)
'writer shame page is missing' is the wordplay.
'writer' becomes 'author' ('author' can be a synonym of 'writer'**).
'shame' becomes 'pity' ('pity' can be a synonym of 'shame').
'page' becomes 'p'.
'is missing' is a deletion indicator.
'pity' with 'p' removed is 'ity'.
'author'+'ity'='AUTHORITY'
'shown by' is the link.
(Other definitions for authority that I've seen before include "Mandate" , "Expert; permission" , "Power to expercise control" , "Power, influence" .)