The most common and most likely answer to this crossword clue is the 1 plus 8 letter word A CAPPELLA
A
C
A
P
P
E
L
L
A
More clues leading to the result A CAPPELLA
- Unaccompanied neighbour of C and R White, female
- Fancy paella, top included, with no accompaniment
- Like barbershop, the creation of R Smythe Fitzgerald
- Unaccompanied, in palace, lap dancing
- A better piano? Fitzgerald is unaccompanied
- A hat on the head of Peter Fitzgerald not accompanied
- Unaccompanied singing in palace – and lap dancing!
- Nearly all clap ape surprisingly singing like this?
- Unaccompanied girl pursuing cartoon character?
- Unaccompanied is better in cooking paella
Buddy explains!

The straight part
We know that "unaccompanied" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unaccompanied = a cappella.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.