Safari 8.0 web process at 100% CPU every time I start Safari after resuming from sleep
Sorry it's not a solution, but just to reassure you that you're not going mad: I have the exact same problem, different URL, but similarly old and unvisited - it's not even an open tab or within top-sites.

However, as well as peaking at 98% CPU usage, I also eventually get  the red error notice in Activity Monitor 'Safari Web content (not responding)' and everything slows down - although Safari is mostly still usable.

I've tried disabling extensions and iCloud sync. Even restarting doesn't remove the old URL.