The most common and most likely answer to this crossword clue is the 9 letter word CELEBRITY
I've seen this crossword clue in The Guardian
C
E
L
E
B
R
I
T
Y
More clues leading to the result CELEBRITY
Buddy explains!

The straight part
We know that "Star" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case star = celebrity.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 CELEBRITY mean?
CELEBRITY noun- A rite or ceremony.
- Fame, renown; the state of being famous or talked-about.
- A person who has a high degree of recognition by the general population for his or her success or accomplishments; a famous person.