Explosive little Edward, climbing, grabbed by worried grown-up (9)
I believe the answer is:
gunpowder
'explosive' is the definition.
(I know that gunpowder is a type of powder explosive)
'edward climbing grabbed by worried grown-up' is the wordplay.
'edward' becomes 'Ed' (short for Edward).
'climbing' shows that the letters should be reversed in order (in a down clue, letters climb up).
'grabbed by' indicates putting letters inside (inserted letters are grabbed inside).
'worried' is an anagram indicator.
'ed' reversed gives 'de'.
'grown'+'up'='grownup'
'grownup' with letters rearranged gives 'gunpowr'.
'de' inserted inside 'gunpowr' is 'GUNPOWDER'.
'little' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for gunpowder that I've seen before include "It's used in gunnery and fireworks" , "and 24: 1605 conspiracy" , "Explosive; type of 23 dn" , "Explosive mixture (of tea?)" , "Explosive mixture - plot of 1605" .)