I've tested it with version 1.3.0 of Xamarin.Google.ARCore and it works fine. Versions 1.6.0, 1.7.0 and 1.8.0 all suffer from the 90 degree issue.
the current integration of ARCore into the Wikitude SDK is coded against the 1.1.0 version of the ARCore library. You can't arbitrarily change versions. Recent releases of ARCore, as you have found out, did include breaking changes that we would need to adopt our implementation to. For now you'll have to use the 1.1.0 version specifically.