Resolved to accept thanks on return, being loyal (9)
I believe the answer is:
dedicated
'loyal' is the definition.
('dedicated' can be similar in meaning to 'loyal')
'resolved to accept thanks on return' is the wordplay.
'resolved' becomes 'decided' ('decide' can be a synonym of 'resolve').
'to accept' is an insertion indicator.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'on return' says the letters should be written backwards.
'decided' placed around 'ta' is 'detacided'.
'detacided' reversed gives 'DEDICATED'.
'being' is the link.
(Other definitions for dedicated that I've seen before include "Customised" , "Devoted to a particular cause or purpose" , "Hard working" , "exclusive" , "Determined" .)