Yes i would definitely take the hard line and tell him you wont see him anymore.
Don't believe his excuses either. I firmly believe that these sort of men like to try and prey on our good natures. Anyone with full cognative function knows that turning up unannounced on somebodies doorstep at 8.15 in the morning is totally rude,unacceptable and out of order. If you continue seeing him he will just do something else futher down the line that is out of order,then he will apologise and you will be in a pattern of bad behaviour followed by a load of sorrys followed by more creepy actions.
I know cos Ive been there and knocking it on the head is the only way to go.
If you wanted a dog you wouldn't even necessarily need a big scary one,sometimes hearing it bark is enough to put people off without even seeing it. My dog is a tiny little toy dog but if you heard him bark you would think he was 4 times that size!