In eight clues, cryptic indications omit reference to parts of answers; these parts must be highlighted, to reveal a word that defines each of the unclued lights. Two unclued lights consist of two words each.
 

Across

1    Quiet exercises by expert (5)
9    Locusts, very large, after jelly and syrup (10)
11    Free to return without a souvenir (5)
14    Sound during festival identified (5)
15    Varied like marks in rug (5)
16    Going out east, slow, short of oxygen (6)
21    Pacific island with prison mostly in concrete (8)
22    Excluded, king and earl sulk (7, two words)
24    Bird’s...