Wow! My blood boils for you on this one! Absolutely 100% unacceptable behavior...and from a supposed "grown-up"!!!
I get annoyed with even 2 minutes early!!! Sounds picky but my morning is precious and I am upfront with parents that time is one of those things I am a stickler about!
I hope you didn't give in and let them in the door one minute before 8!!!