My apologies, question left out an important component. I was looking for a way to log uncaught exceptions with wildfly 9.0.2 using log4j2. I've added that as a module to wildfly.
It might be possible to use log4j as the log manager in a standalone container, but it won't work in a managed domain. You have to remove the logging subsystem and logging extension from WildFly. Then you need to modify the modules/system/layers/base/org/jboss/logmanager/main/jboss-logmanager-*.jar file and remove the META-INF/services/java.util.logging.LogManager file. Then ensure your log4j module ends up on the system modules.
Just note once you do this managed domain containers will no longer work. You'd also lose the ability to configure logging via management like CLI or the web console.
James R. Perkins