Catholic dude demolishes head of school on TV (9)
I believe the answer is:
broadcast
'demolishes head of school on tv' is the definition.
I can't tell whether this defines the answer.
'catholic dude' is the wordplay.
'catholic' becomes 'broad' ('broad' can be similar in meaning to 'catholic').
'dude' becomes 'cast' (I can't explain this - if you can you should believe this answer much more).
'broad'+'cast'='BROADCAST'
Can you help me to learn more?
(Other definitions for broadcast that I've seen before include "Show" , "Send out over the airwaves" , "Transmit by radio or television" , "Transmission" , "Transmit (programme)" .)