Plugin module development with daily build on JDK9

Hello,

as the JDK9 branch has been merged into default:
How can I use it for module development?

I'm running netbeans-dev-201703120002 on Java9, with the following results:
1. I cannot set the source level of modules to Java 9.
2. I cannot open existing modules (which worked until merge)
3. New modules can be created. However, dependencies don't work (which 
is essentially the same issue as [2])

[2] IMHO is most important, currently - sth. is broken in dependencies 
management.

Kind regards
Peter