Please can i have some help. Have one to finish the easy one but can't get going with cryptic.
easy 4a Dietetic drink (6) -o-s-t
cryptic 9a It means the end of a union (7,6) last letter E
2d One must be patient with it for a long time (6,7) no letters
6d Great ambition of the pyromaniac (7,6) no letters
21a Religious split? (6,2,5) ----c- o- -----