Landlord at home with new guardian (9)
I believe the answer is:
innkeeper
'landlord' is the definition.
(I've seen this before)
'home with new guardian' is the wordplay.
'home' becomes 'in' ('he's home' can mean 'he's in').
'with' says to put letters next to each other.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'guardian' becomes 'keeper' (keeper is a kind of guardian).
'in'+'n'+'keeper'='INNKEEPER'
'at' is the link.
(Other definitions for innkeeper that I've seen before include "Job" , "For example, Mistress Quickly" , "Pub licensee" , "Pub landlord" , "Publican" .)