The most common and most likely answer to this crossword clue is the 12 letter word HOSPITALISED
I've seen this crossword clue in The Daily Telegraph
H
O
S
P
I
T
A
L
I
S
E
D
Buddy explains!
The straight part
We know that "put in 9" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case put in 9 = hospitalised.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 HOSPITALISED mean?
HOSPITALISED adjective- Being treated in a hospital
- To send to hospital; to admit (a person) to hospital.
- To render (a building) unfit for habitation, by long continued use as a hospital.
- (of an injury, illness, event, or person) To cause (a person) to require hospitalization.