The most common and most likely answer to this crossword clue is the 9 letter word OPERATIVE
I've seen this crossword clue in Financial Times
O
P
E
R
A
T
I
V
E
More clues leading to the result OPERATIVE
- Working poet I rave about
- Workman excited over pieta
- Significant work, musical, about to be brought back
- American detective in force
- Skilled worker in force
- Worker has to choose clothing a long time before I have
- Worker old theatre brought back with return of musical show
- Upcoming musical about Post Office worker
- Significant worker, one having special skills
- Crucial time I have after event at Sadler’s Wells, maybe
Buddy explains!

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 OPERATIVE mean?
OPERATIVE noun- An employee or other worker with some particular function or skill.
- A spy, secret agent, or detective.
- A participant in an operation.
- Effectual or important.
- Functional, in working order.
- Having the power of acting; hence, exerting force, physical or moral; active in the production of effects.
- Producing the appropriate or designed effect; efficacious.
- Based upon, or consisting of, a surgical operation or operations.