Upsetting trend Independent's spoken about leader (9)
I believe the answer is:
editorial
'leader' is the definition.
(I've seen this before)
'upsetting trend independent's spoken about' is the wordplay.
'upsetting' says the letters should be written backwards.
'trend' becomes 'tide' (I've seen this before).
'independent' becomes 'i'.
'spoken' becomes 'oral' ('oral' can be similar in meaning to 'spoken').
'about' indicates putting letters inside.
'tide' in reverse letter order is 'edit'.
'i' placed into 'oral' is 'orial'.
'edit'+'orial'='EDITORIAL'
(Other definitions for editorial that I've seen before include "considered view on paper" , "Article expressing the views of the publication" , "Article written" , "bit of paper" , "(Paper's) leader" .)