All,
I did get it to work, but I tried so many things, I don't know the secret combination. Originally, when I first upgraded to SIERRA and did the steps on militaryCAC.com, my certificates were read, but didn't allow me to enter a pin on the web page, even though there were already in the system.keychain folder. I then went back and used the militarycac website to delete all CAC enables. Finally, I followed Ryans, recommendation and moved the downloaded certs to my desktop. Then when I double clicked on those files, I was selected 'system' from dropdown menu. ('login' is default) I then cleared all cached webpages and browsing history in both CHROME and SAFARI, went to the CAC enabled website, and then everything worked. I don't know the secret sauce, but that is exactly what I did.
Jeremy