Belief Manx cat lives with Ralph Fiennes, currently (9)
I believe the answer is:
pantheism
'belief' is the definition.
(pantheism is a kind of belief)
'manx cat lives with ralph fiennes currently' is the wordplay.
I cannot really see how this works, but
'lives' could be 'is' ('be' can be a synonym of 'live') and 'is' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for pantheism that I've seen before include "Seeing god in nature" , "Belief that God is in everyting" , "Readiness to believe in all or many gods" , "Widespread belief" , "Religion" .)