Extensive list of actors for TV show (9)
I believe the answer is:
broadcast
'tv show' is the definition.
'broadcast' can be an answer for 'show' (broadcast is a kind of show). I'm not sure about the 'tv' bit.
'extensive list of actors' is the wordplay.
'extensive' becomes 'broad' (similar in meaning).
'list of actors' becomes 'cast' (I can't justify this - if you can you should give a lot more credence to this answer).
'broad'+'cast'='BROADCAST'
'for' is the link.
Can you help me to learn more?
(Other definitions for broadcast that I've seen before include "Send out over the airwaves" , "Show" , "Transmit by radio/TV" , "Put on the air" , "Transmit by radio or television" .)