The most common and most likely answer to this crossword clue is the 8 plus 1 letter word REDCOAT} –
R
E
D
C
O
A
T
}
â
€
“
Buddy explains!

The straight part
We know that "old soldier" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old soldier = redcoat} –.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 REDCOAT} – mean?
REDCOAT} – noun- A British soldier, especially during the American Revolution.
- A member of the entertainment staff at Butlin's holiday camps in the United Kingdom, who wear red blazers.
- A fox.