Last year in kindergarten, my son wasn't allowed off the bus unless a parent (or adult associated with my son that the driver recognized) was at the stop. This year, he's at a different stop, 4 houses down and across the street from us. I went with him am/pm until about Christmas. Now, I watch from the porch. We can see the bus as it goes down the next street (before his stop), so he doesn't leave our house until about 2 minutes before the bus arrives - usually getting there at the same time. Then, he has to wait for the bus driver's signal to cross the street. Same routine in the afternoon.
Next year when my youngest will be in kindergarten, I'll be back at the bus stop as required. But, I'd probably be there anyway since I don't know that I'd trust them together (though in reality, they're very responsible kids - but still 5 & 7).
I, too, think you have to go with your gut feeling and your child's maturity... and you know your neighborhood. However, I think our district goes a bit overboard with the stops... If there are multiple children on the same street, the bus will stop at *every* corner and let 1-2 kids off - even high schoolers. I understand be extra-cautious with the little ones, but it seems a little much to be behind a bus that will stop at 8 corners in a row only to let 1 HSer off each time. Just my opinion.