Romantic musician, seconds before, excited Andre (9)
I believe the answer is:
serenader
'romantic musician' is the definition.
(someone serenading a love interest)
'seconds before excited andre' is the wordplay.
'seconds' becomes 's'.
'before' becomes 'ere' (poetic term for 'before').
'excited' indicates anagramming the letters.
'andre' anagrammed gives 'nader'.
's'+'ere'+'nader'='SERENADER'
(Other definitions for serenader that I've seen before include "Singer" , "Performer" , "a musical swain" , "Lovesick guitarist perhaps" .)