The most common and most likely answer to this crossword clue is the 8 letter word HOTHEADS
I've seen this crossword clue in The Guardian
H
O
T
H
E
A
D
S
Buddy explains!

The straight part
We know that "agitators" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case agitators = hotheads.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 HOTHEADS mean?
HOTHEADS noun- One who angers easily or goes in search of arguments or fights.
- One who reacts quickly and without thinking carefully first