Film director in story by composer (9)
I believe the answer is:
spielberg
'film director' is the definition.
'spielberg' can be an answer for 'director' (I have seen 'Director of Jaws' mean 'spielberg' so perhaps 'director' could also mean 'spielberg'). I'm not sure about the 'film' bit.
'in story by composer' is the wordplay.
'in story' becomes 'spiel' (I am not sure about this - if you are sure you should believe this answer much more).
'by' says to put letters next to each other.
'composer' becomes 'berg' (Alban Berg, s88l - s9il).
'spiel'+'berg'='SPIELBERG'
Can you help me to learn more?
(Other definitions for spielberg that I've seen before include "Director of Jaws" , "Schindler's List director" .)