The most common and most likely answer to this crossword clue is the 9 letter word PHYSICIST
I've seen this crossword clue in Financial Times
P
H
Y
S
I
C
I
S
T
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 PHYSICIST mean?
PHYSICIST noun- A person whose occupation specializes in the science of physics, especially at a professional level.
- A believer in the theory that the fundamental phenomena of life are to be explained upon purely chemical and physical principles (opposed to vitalist).