The most common and most likely answer to this crossword clue is the 9 letter word ORRISROOT
I've seen this crossword clue in Financial Times
O
R
R
I
S
R
O
O
T
Buddy explains!
The straight part
We know that "a perfume ingredient" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a perfume ingredient = orrisroot.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.