The most common and most likely answer to this crossword clue is the 9 letter word PLAYMATES
I've seen this crossword clue in The Guardian
P
L
A
Y
M
A
T
E
S
More clues leading to the result PLAYMATES
Buddy explains!

The straight part
We know that "Friends" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case friends = playmates.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 PLAYMATES mean?
PLAYMATES noun- A companion for someone (especially a child) to play with.
- A female who has appeared as the centerfold in Playboy magazine.
- A person's lover.