I don't know why you missed it, but it mentions both isomorphism (code that can be run client side or server side) and the virtual DOM (web components, etc...).
"Use some of the libraries on the server with NodeJS. i.e. DI." - some, and I'd expect an explicit mentioning of isomorphism if it were possible at the moment to render it on the server side.
Shadow DOM != Virtual DOM. I mean the React-style Virtual DOM.
Virtual DOM is (typically) a pure JavaScript object-based DOM representation that gets somehow flushed to actual DOM (or to WebGL or anything else). You as the programmer use the Virtual DOM directly and try to avoid talking to the real DOM underneath. Virtual DOM has a few advantages, but the one that stands out in today's browsers is limiting DOM thrashing where you query the DOM (requiring an expensive recalc) and then modify the DOM (invalidating what was recalc'd) in a loop.
Or do you mean the hint that some of the code can run server-side? That seems obvious, and is not in itself isomorphism.
If a platform claims to support isomorphism, I expect it to render server-side with zero drama/workarounds/blog posts. Support means that producing fully-rendered html is a core part of the product and documentation, not something glued on the side or pieces to reassemble on your own.
From the wording, it looks like Aurelia isn't there yet?