GCC trunk is open for general development (Stage 1) until the end
of Nov 11th after which it will transition to bugfixing mode (Stage 3)
which in turn will end Jan 6th after which only regression and
documentation fixes will be possible.
This means you have an additional three weeks to push feature
changes for GCC 9.
Note bugs have not yet been prioritized thoroughly so there's no
meaningful Quality Data yet.