It seems likely that the first release candiate from Java 9 will be delayed to the 21st September from 27th July. The delay is to address concerns that resulted in JSR 376 not being approved -- the Java Platform Module System aka. Project Jigsaw.
This is the project that was mean't to be in Java 7, then 8, now 9 so with it's history those involved have been stressing that they expect this to be resolved within the permitted 30 days and that they had to vote on what was submitted. i.e. They were aware some of their concerns were being addressed while they spoke.
It does sound like all will be well and hopefully we can start to escape Jar hell and embrace requires and exports.
Changes for Java 9 here: https://docs.oracle.com/javase/9/whatsnew/toc.htm