Trophy firm raised commotion about army order? (8)
I believe the answer is:
octopoda
'army order?' is the definition.
(octupi have lots of 'arms' so they are 'arm-y')
'trophy firm raised commotion about' is the wordplay.
'trophy' becomes 'pot' (I've seen this before).
'firm' becomes 'co' (a firm is a company).
'raised' says the letters should be written in reverse.
'commotion' becomes 'ado' (ado is a kind of commotion).
'about' is a reversal indicator.
'pot'+'co'='potco'
'potco' written backwards gives 'octop'.
'ado' reversed gives 'oda'.
'octop'+'oda'='OCTOPODA'
(Another definition for octopoda that I've seen is " Molluscs".)