Keen favourites returning to dance (9)
I believe the answer is:
quickstep
'dance' is the definition.
(I know that quickstep is a more specific form of the action dance)
'keen favourites returning' is the wordplay.
'keen' becomes 'quick' (I am not sure about this - if you are sure you should believe this answer much more).
'favourites' becomes 'pets' ('pet' can be a synonym of 'favourite').
'returning' says the letters should be written backwards.
'pets' written backwards gives 'step'.
'quick'+'step'='QUICKSTEP'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for quickstep that I've seen before include "Fast foxtrot" , "Fast dance" , "dance music" , "Lively dance" , "Modern ballroom dance" .)