I think it should be fine. I did that a lot
she forgot to replace on the 7th day of the ring free week and instead replaced it on the 8th day
my guess is that she will be fine. Was she on her period at the time or was she just didn't change her ring on the right day?
Also it could take up to a couple of weeks for your body to adjust to the hormones so either way pregnancy may occur
No the Nuva ring has to be in place to work and on CD 9 I would say there is a very good chance she could be pregnant