Yours truly's getting in a state for passion (9)
I believe the answer is:
animation
'passion' is the definition.
(thesaurus)
'yours truly's getting in a state' is the wordplay.
'yours truly's' becomes 'im' (I'm).
'getting in' means one lot of letters goes inside another.
'state' becomes 'nation' ('nation' can be a synonym of 'state'**).
'a'+'nation'='anation'
'im' put within 'anation' is 'ANIMATION'.
'for' acts as a link.
(Other definitions for animation that I've seen before include "Vigour; film technique" , "Film technique; lively state" , "Cartoon-making art" , "(State of) being full of life" , "Liveliness and enthusiasm" .)