The most common and most likely answer to this crossword clue is the 5 plus 4 letter word ALICE BAND
I've seen this crossword clue in The Guardian
A
L
I
C
E
B
A
N
D
More clues leading to the result ALICE BAND
- Lockkeeper catching something cold and black in a net
- Pests in a group that may cover the hair
- A country in which you’ll see black diamonds before lock-keeper?
- An infesting ring that may be in girl’s hair
- Girl audibly forbidden to see lock-keeper
- Something in girl’s hair, daughter after an order designed to keep nits away?
- It could keep the shock from one’s eyes
- One cutting frayed cable, even if it partially insulates shock?
- Accessory upset Celia’s orchestra
- Girl fronting group wanting ribbon for hair . . .
Buddy explains!

The straight part
We know that "Something in girl’s hai" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case something in girl’s hai = alice band.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.