/t/5694625/shadow-test-access-check-here-info

There is a stickied post on the community forum that says [Shadow Test Access] <----- !CHECK HERE INFO! (/t/5694625/shadow-test-access-check-here-info) apparently its unstable but i personally haven't tried it.
also it has a password its "i am aware that these are test builds"

YeetPatch, its under unstable. 0.8 saves aren't compatible with 0.9, but you can use the mailbox to transfer items.