On waves, great to come up again (9)
I believe the answer is:
resurface
'come up again' is the definition.
('surface' can be a synonym for 'come up' so perhaps 'resurface' is OK for 'come up again')
'on waves great' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'waves' becomes 'surf' (surf can mean foam from waves).
'great' becomes 'ace' (ace can informally mean very good).
're'+'surf'+'ace'='RESURFACE'
'to' acts as a link.
(Other definitions for resurface that I've seen before include "Come back up to the top of deep water" , "Bob up" , "Put a new coating on" , "make another appearance" , "Emerge again" .)