I let DD (9) and friend go to the shop alone

[Mrschocolate]

DD (9 tomorrow) has a friend round for a sleepover who is 10 in September.
They wanted to go to the shop to get sweets before BGT and I said yes gave them money and let them go.
The shop is about 3 minutes away if that and there is one road to cross however there are traffic lights right outside the shop. Her friend had a mobile which has our home number on it.
Also I can see the route to the shop from my bedroom window DD knows this so she wouldn't be tempted to mess around though I don't think she would anyway because her and her friend are both very sensible.
They went and came back within 10 minutes and they were quite happy.

SIL called as they came through the door and I told her where they had been and she went mad saying that they could of died and I was irresponsible. So AIBU? Does anyone have DCs of a similar age and would they let them go to the shop etc

well, they weren't her children so time to tell her to ratchet down the drama.

If we leave the other child out of the equation, as I think we must, then your SIL is being a total catastrophist. Assure her warmly you will never subject her babies to this if they are in your care as she has made her feelings plain, but as for your dd, not her call. Or get your DP (I assume she is his sister) to manage her. Not your problem.

Easier said than done. I do know. My DB is married to a perfect mother. Gah!