Hey guys - just FYI here - I upgraded from 4.1 to 5.1 and ran into this issue doing the "Simple install". Simple test - telnet to 9443 - if it doesn't answer, you know something is missing. Mine was missing. Simple install didn't install "VMware vSphere Web Client" - which if you read the fine print on the right side while it's highlited says "installs the Web Client server" ... Not obvious at all, and I hope it helps someone else. After installing, :9443 is open and working! 
Enjoy,
DaveM