Novel name used occasionally with Handel's last Messiah (8)
I believe the answer is:
emmanuel
'messiah' is the definition.
(I have seen 'The Messiah ' mean 'emmanuel' so perhaps 'messiah' could also mean 'emmanuel')
'novel name used occasionally with handel's last' is the wordplay.
'novel' becomes 'emma' (I've seen this before).
'name' becomes 'n' (common abbreviation e.g. on forms).
'occasionally' means one should take alternating letters.
'with' means one lot of letters go next to another.
'last' indicates one should take the final letters.
The final letter of 'handel' is 'l'.
The alternate letters of 'used' are 'ue'.
'emma'+'n'+'ue'+'l'='EMMANUEL'
(Other definitions for emmanuel that I've seen before include "Messiah's name (Is. 7.14)" , "Man" , "Lame menu (anag) - Cambridge college" , "Boy" , "The Messiah" .)