Dome alarm went off - sensational stuff (9)
I believe the answer is:
melodrama
'sensational stuff' is the definition.
'melodrama' can be an answer for 'stuff' (I have seen 'emotive stuff' mean 'melodrama' so perhaps 'stuff' could also mean 'melodrama'). I'm not sure about the 'sensational' bit.
'dome alarm went off' is the wordplay.
'went off' indicates an anagram.
'dome'+'alarm'='domealarm'
'domealarm' anagrammed gives 'MELODRAMA'.
Can you help me to learn more?
(Other definitions for melodrama that I've seen before include "sensational affair" , "emotive stuff" , "Sensational theatre piece" , "Play of extravagant action" , "Extravagantly styled play" .)