Surprisingly, Stella with ice is heavenly (9)
I believe the answer is:
celestial
'heavenly' is the definition.
(synonyms)
'surprisingly stella with ice' is the wordplay.
'surprisingly' is an anagram indicator (a surprising ordering of the letters).
'with' is a charade indicator (letters next to each other).
'stella' after 'ice' is 'icestella'.
'icestella' is an anagram of 'CELESTIAL'.
'is' acts as a link.
(Other definitions for celestial that I've seen before include "Relating to the heavens" , "Heavenly" .)