Landlord's private stock included (9)
I believe the answer is:
innkeeper
'landlord's' is the definition.
(I've seen this before)
'private stock included' is the wordplay.
'private' becomes 'inner' (as in one's private or inner thoughts).
'stock' becomes 'keep' (I've seen this before).
'included' indicates putting letters inside.
'inner' placed around 'keep' is 'INNKEEPER'.
(Other definitions for innkeeper that I've seen before include "Pub landlord" , "Accommodating type" , "Tavern owner" , "Manager who made extra provision for visitors" , "Publican" .)