8a: officer in charge of a military unit (10) ?O?M?N?A??
9a:audacity(4) N?C?
14a:at the top of the tree?(10) S?C???S?U?
20a:lacking strength and substance (5-5) ?I?H???S??
23a:chemical setting agent (8) ?I?A????
28a:food & drink as a source of strength(10) ??????A?C?
5d:food high in filling carbohydrates(6) ???D??
17d:free-fall artist(8) S???I???
21d:fantasy, quaintness(6) ??????
24d:allay(4)????