According to http://buildbot.net/ - BuildBot supports Python 3.6 now. Please add it to PYTHON_TARGETS.
Yes, it does, so did 0.9.7, but it is a work in progress to get all it's deps updated to support python-3.6. As it was I was slow to get 0.9.7 in the tree just to get all the deps to support python-3.5. Feel free to work on the deps in a local overlay. Do the testing and submit bugs for the updates. The python team and other maintainers would appreciate the help.
FYI, upstream buildbot still regards python 3 as experimental. Not yet fully debugged. But that will take more users testing it on python 3. So for production use, it is still recommended to use python-2.7 until you are satisfied your builders are working correctly with python 3. The 0.9.8 release requires the latest twisted release which was mostly python 3 fixes brought about by buildbot testing with python 3.
Buildbot has py3.6 added for >= buildbot-0.9.13