Y6 for my eldest so 11. There was generally 30 minutes between her getting in and my husband returning home, she also walked home with friends at this time too.
She had a ticklist for the 1st few weeks -
-Bag and coat in safe place
-Open back door, let dog out. Once dog in, lock back door.
If there was an emergency in that short space of time, she was to ring me, her dad or grandad and door was not to be answered to anyone. She was also taught safest route in a fire etc, at a young age so was aware of how to get out safely.
If she wanted food, we had snacks.
Now both my nearly 13 year old (y8) and nearly 11 year old (y6) make own way home (with little guidance to y6 child by grandad) and they are home until either myself or husband arrive home 45 mins to an hour later.
It has been a very staggered process which would have stopped had either of them had shown me they were unsafe but I want them to get independence as I did at that age.