Suitable Punishment

[Carsarelife]

DD is almost 9. She got out of the bath last night and asked me to trim her hair so it's straight at the bottom. I told her I have a headache and I will do it for her in the morning. She seemed to accept this and went to bed after drying her hair it was around 9pm.
This morning I woke up and I noticed she has cut her hair herself. I feel so upset. Due to the fact she has lied. I asked her outright if she cut her hair and she said no. Myself and eldest DD have found the hair.
For context I am a hairdresser so do have hairdressing scissors. Not lying around but in a hold-all in hallway cupboard.
It's her birthday next week.

What is a suitable punishment for this?

Why would you punish her for it? Understandably, it is not okay that she has lied but I do not believe it's that severe, it just deserves a conversation about being patient and not lying to people, to ensure that she understands. I don't believe punishment is necessary for this. I'd tell her about how doing it herself could go wrong and that if she waited a little longer that you would've helped her.

Because she asked me to cut her hair and I said no. She has cut a big chunk off the bottom of her hair as she wouldn't wait.
She has gone to cupboard and got my scissors from my bag.
I've already taken her iPad and said no iPad for a week. I can just let her cut her own hair and think it's acceptable to do that.

The punishment is her hair looking like a 9 year old cut it, there no need for anything else. It's a natural consequence.

I'm actually fuming about it as I think she's old enough to know better. It's not like she's 4 or 5.

She is obviously not old enough to know better because she did it.

Now her hair looks terrible.

That is the end of it.

Why would you punish her more? She's done something stupid and now needs a haircut to fix it. If you really really want to, I guess you could say she needs to give you a week's allowance towards what a haircut would cost, but honestly I'd not punish her more.