The most common and most likely answer to this crossword clue is the 9 letter word SCENARIOS
I've seen this crossword clue in The Times
S
C
E
N
A
R
I
O
S
Buddy explains!

The straight part
We know that "circumstances" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case circumstances = scenarios.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 SCENARIOS mean?
SCENARIOS noun- An outline of the plot of a dramatic or literary work.
- A screenplay itself, or an outline or a treatment of it.
- An outline or model of an expected or supposed sequence of events.