There are several discussions on this subject and new sync feature cache them on the desktop , but it not necessary you can copy them to another dectop or server , hence XMPie plug-in may not sync them or copy them as well. But since it should be used with Adobe server that use CC the question is if inDesign Server CC supports it or not and if it can sync those fonts , since in general XMPie should not even copy them or package them .
I asked one of our experts to place some comment on the subject since I think in general font synchronization is an important subject .
You can read some info here :
... sending you the real OTF fonts that you’re syncing from Typekit, but hiding them on your computer and making them accessible to your apps through the Creative Cloud app. It’s perfectly understandable why they’d obscure it to a degree since you’re “renting” the fonts, and since it works seamlessly in apps, there’s nothing to really complain about. It’s just not quite as obstructed as you might have imagined it’d be — and it’s actually bringing you the real fonts, not “hacking” web fonts to appear in your web apps and streaming them from the cloud live when you’re using them, as I thought it might be when I at first only found the XML files in the Creative Cloud sync folder.