Appropriate punishment for a 9 year old

[Karmelita]

My 9-year-old DD confessed (after I gave her the "raised eyebrows look" and some evidence) that she intentionally peed on the (very thick) carpet in her bedroom because her friend (who was visiting on that day) dared her to. Before finally confessing, DD insisted (for 4 days) that it was all the cat's fault.
As hilarious as this might sound, I'm sad that she can be influenced so easily by a peer.
Anyway, I've grounded her for 2 weeks and revoked access to the tablet and TV. Do you think it's harsh?

I'd be asking her to help clean it up and showing her why it's unacceptable- the smell, the hygiene and how silly to do a dare like that - I remember being child minded by a friend of my mum's who used to wee on floor on purpose and say it was his baby brother (in nappies!!)
I think two week ban isn't effective. Maybe few days then move on.

I may have read this wrong but it sounds like you're saying you punished her for confessing, which would be counterproductive if you want her to be honest with you in future.
I'm no expert in any way but i would have thought a discussion about why we should always use the toilet and she can help clean the carpet regardless to realise what the the actual consequences of the action are. Just to make sure the consequence is related to the undesirable behaviour rather than just a standard one size fits all punishment.