Band's regular engagement in leader's office, but no piano (9)
I believe the answer is:
residency
'band's regular' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'engagement in leader's office but no piano' is the wordplay.
I cannot quite understand how this works, but
'leader's' could be 'es' (I've seen this in other clues) and 'es' is present in the answer.
'office' could be 'den' (I've seen this in other clues) and 'den' is located in the answer.
The remaining letters 'ricy' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for residency that I've seen before include "Fact of living in a place" , "circumstance of living in a particular place" , "Home" , "Position in house" , "temporary post as artist" .)