The most common and most likely answer to this crossword clue is the 9 letter word CHARIVARI
I've seen this crossword clue in The Times
C
H
A
R
I
V
A
R
I
More clues leading to the result CHARIVARI
- Gay vicar embraces female spy Mata, creating uproar
- Row in church turning one Gershwin against himself
- Hubbub exposed in daily, one modified when editor’s absent
- Vicar with hair looking ridiculous in mock serenade
- Toast controversial match official in 11, causing rumpus
- Din confused arch rival briefly, I gathered
- Vicar with hair restyled for noisy wedding party
- Eccentric vicar receiving hair transplant makes a hell of a noise
- Unholy din as Indian stood up, having been sat in slightly rickety chair
- Row in church about infighting among Provos
Buddy explains!

The straight part
We know that "Hubbub" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case hubbub = charivari.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 CHARIVARI mean?
CHARIVARI noun- The noisy banging of pots and pans as a mock serenade to a newly married couple, or similar occasion.
- (by extension) Any loud, cacophonous noise or hubbub.