Sponsor to follow up yearly fee (9)
I believe the answer is:
godparent
'sponsor' is the definition.
(I know that godparent is a type of sponsor)
'follow up yearly fee' is the wordplay.
'follow' becomes 'dog' (dog can mean to follow or torment).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'yearly fee' becomes 'parent' (I can't explain this - if you can you should believe this answer much more).
'dog' in reverse letter order is 'god'.
'god'+'parent'='GODPARENT'
'to' is the link.
Can you help me to learn more?
(Other definitions for godparent that I've seen before include "Pet dragon (anag)" , "as one responsible for charge" , "Religious guardian" , "Baptism sponsor" .)