The most common and most likely answer to this crossword clue is the 9 letter word DEPUTISES
I've seen this crossword clue in The Daily Telegraph
D
E
P
U
T
I
S
E
S
Buddy explains!

The straight part
We know that "Delegates" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case delegates = deputises.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 DEPUTISES mean?
DEPUTISES verb- To make (someone) a deputy; to officially empower.
- To make or name as a substitute.
- To act as a deputy.