The default.properties file has added JRE exports for jre-1.9, however these are not picked up. Also there is no definition for ee-1.9 or eecap-1.9.
Java 9 provides the following system properties:
java.runtime.name: Java(TM) SE Runtime Environment
java.specification.name: Java Platform API Specification
java.specification.vendor: Oracle Corporation
... and default.properties uses the value of java.specification-version as the suffix to ee-, eecap- and jre-*. We are expecting "1.9" but the actual value is just "9".
This problem causes basically ALL bundles to fail to resolve on Felix 5.6.2 under Java 9.