I tried testing on a version of JDK9 that has the Java EE modules in SE removed using jlink. The following errors occurred.

[java] [java] Caused by: wsimport failed
     [java] [java] at com.sun.tools.ws.ant.WsTask2.execute(WsTask2.java:432)
     [java] [java] at com.sun.tools.ws.ant.WsImportBase.execute(WsImportBase.java:581)
     [java] [java] at com.sun.tools.ws.ant.WsImport.execute(WsImport.java:100)
     [java] [java] at com.sun.tools.ws.ant.WsImport2.execute(WsImport2.java:52)
     [java] [java] at weblogic.wsee.tools.clientgen.jaxws.ClientGenImpl.execute(ClientGenImpl.java:214)
     [java] [java] ... 18 more
     [java] [java]
     [java] [java] Total time: 20 seconds
     [java] [java] [clientgen] error: module not found: java.xml.ws


The references to –add-modules are in

com/sun/tools/ws/wscompile/WsgenTool.java
com/sun/tools/ws/wscompile/WsimportTool.java

After I hacked around that, I’m getting
    [java] [java] [clientgen] javac: option -Xbootclasspath/p: not allowed with target 1.9
     [java] [java] [clientgen] compilation failed, errors should have been reported