Cheerio and see you later, possibly in food banks (9)
I believe the answer is:
farewells
'later possibly in food banks' is the definition.
Although both the answer and definition are plural nouns, I cannot understand how they can define each other.
'cheerio and see you' is the wordplay.
'cheerio' becomes 's' (I can't justify this - if you can you should give a lot more credence to this answer).
'and' is a charade indicator (letters next to each other).
'see you' becomes 'farewell' (both are ways of saying goodbye).
's' put after 'farewell' is 'FAREWELLS'.
Can you help me to learn more?
(Other definitions for farewells that I've seen before include "They may be fond" , "spoken last words" .)