The most common and most likely answer to this crossword clue is the 9 letter word SPECTATOR
I've seen this crossword clue in The Times
S
P
E
C
T
A
T
O
R
More clues leading to the result SPECTATOR
- Periodical shows unusual tact in prose composition
- Turn chopped fungi over for observer
- Publication one found at sports event
- Heard of mark on potato publication
- Onlooker’s cheers welcomed by policeman dropping in
- Magazine I’m not involved in?
- Onlooker volunteers to feed unpopular police officer?
- Witness putting King Edward on spot before audience?
- Look, article having been placed last by mainly right-wing publication
- Magazine’s prose arranged with tact
Buddy explains!

The straight part
We know that "Magazine" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case magazine = spectator.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 SPECTATOR mean?
SPECTATOR noun- One who watches an event; especially, one held outdoors.