The most common and most likely answer to this crossword clue is the 9 letter word PRIMARIES
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More clues leading to the result PRIMARIES
Buddy explains!

The straight part
We know that "hustings" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case hustings = primaries.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 PRIMARIES mean?
PRIMARIES noun- A primary election; a preliminary election to select a political candidate of a political party.
- The first year of grade school.
- A base or fundamental component; something that is irreducible.
- The most massive component of a gravitationally bound system, such as a planet in relation to its satellites.
- A primary school.
- Any flight feather attached to the manus (hand) of a bird.
- A primary colour.
- Primary site of disease; original location or source of the disease.
- A directly driven inductive coil, as in a transformer or induction motor that is magnetically coupled to a secondary
- To challenge (an incumbent sitting politician) for their political party's endorsement to run for re-election, through running a challenger campaign in a primary election, especially one that is more ideologically extreme.
- To take part in a primary election.