The SA was established well. So that part indeed seems to work ok. But I'm lost as to why you cannot ping through that tunnel. Have you set leftsourceip and rightsourceip? Even then I want to know why no route was added by pluto. I have no Centos/*swan combination running with the same version as you do.
So, I'm in the process of setting up two brand new IPsec hosts to simulate what you are seeing (or not). This will take a few minutes.
Could this by a routing problem at my VPS hosting company?
No, it means that the packet that is supposed to go through the tunnel is going out via your default gateway, and gets (rightfully) blocked one or a few hops further away when it tries to escape towards the internet.
So, it definitely is a routing problem on hour ipsec host, caused by the missing route that should have been added by libreswan, and was not, or was added and immediately removed afterwards.