Karaf support the JDK9+ since 4.2.0 but when starting with the arquillian the error is

-Djava.endorsed.dirs=/path/to/apache-karaf-minimal-4.2.0/lib/endorsed is not supported.

The possible fix could be with KarafManagedDeployableContainer.java and should not pass the "-Dendorsed" argument when the JDK version >= 9