The Jetty 9 module system has intelligence about the buildup of Jetty based on enabled modules or not. This includes XML (with proper execution ordering), properties, and libraries.
Obviously, since you are stuck on maven/gradlew, the last part about libraries is moot.
However, the proper "glue" for Jetty's modules is the XML, either use the LikeJettyXML example or use the XML itself.
Note: the XML is available via maven on the "config" classified artifacts.