the new (soon to be released) Intel XDK build system also supports use of the new cordova-plugin-wkwebview-engine for iOS 9 devices which allows the use of the WKWebView (using it on iOS 8 devices automatically falls back to the default UIWebView) -- this will provide substantially improved performance on iOS 9 devices.
Is this related to the current XDK errors when I try to add the WKWebView plugin?
Error: Plugin "CordovaWebServer" failed to install.
Error: Plugin "" failed to install.
Error: Could not retrieve plugin dependencies for WKWebView Poly '.
Error: Plugin WKWebView Poly failed to install.
It can't install the CordovaWebServer, so it can't install Telerik's WKWebView plugin.
I was guessing it's becaused you need a WebServer to send our game data to the WKWebView, because in iOS8, it would not allow loading from the local files but in iOS9 it does.
Something along those lines?