The most common and most likely answer to this crossword clue is the 9 letter word REDSTARTS
I've seen this crossword clue in The Guardian
R
E
D
S
T
A
R
T
S
Buddy explains!
The straight part
We know that "layers /(9)" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case layers /(9) = redstarts.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 REDSTARTS mean?
REDSTARTS noun- Any of various insectivorous ground-feeding birds, mainly of the genus Phoenicurus. Many of the species have a red tail.
- An unrelated species of warbler native to the Americas, Setophaga ruticilla