Sponsor of studio session perhaps who logs good and bad acts (9,5)
I believe the answer is:
recording angel
'studio session perhaps who logs good and bad acts' is the definition.
The definition suggests a singular noun which matches the answer.
'sponsor' is the wordplay.
I cannot really see how this works, but
'sponsor' could be 'angel' (angel is a kind of sponsor) and 'angel' is found in the answer.
The remaining letters 'recording' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for recording angel that I've seen before include "Spirited observer" , "who notes your every move" , "who gives financial backing to pop-groups?" , "one noting all faults?" , "Chronicler" .)