The most common and most likely answer to this crossword clue is the 9 letter word EXPLOSIVE
I've seen this crossword clue in Independent
E
X
P
L
O
S
I
V
E
More clues leading to the result EXPLOSIVE
Buddy explains!

The straight part
We know that "Fiery" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fiery = explosive.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does EXPLOSIVE mean?
EXPLOSIVE noun- Any explosive substance.
- With the capability to, or likely to, explode.
- Having the character of an explosion.
- Shocking; startling.
- Easily driven to anger, usually with reference to a person.