By any chance are you packaging a JAR inside your "WEB-INF/lib" (or inside any of your custom module) which is including the class "javax.sql.DataSource" ? Or "org.jboss.as.connector.subsystems.datasources.WildFlyDataSource". If yes then you are not supposed to include any if such JAR inside your application lib.
We are not using any lib, the problem i am facing is in wildfly 9.0.2.Final but same war if i deploy in wildfly 8.1.0.Final it is working.
Did you get any solution for this issue ?
I am facing exact same problem with my application while moving from 8.2 to 9.0.2 .
I got the issue with my application.
In one of my custom modules , we have jboss-j2ee.jar , which contains class "javax.sql.DataSource". I removed it and it worked fine !
Thanks Jay for pointers.