This is a windows fastdebug build from the top-level of the source:

# Java(TM) SE Runtime Environment (build 1.9.0-internal-fastdebug-201409030732.staffan.jdk9-hs-rt-b00)
# Java HotSpot(TM) Client VM (build 1.9.0-internal-201409030732.staffan.jdk9-hs-rt-b00, mixed mode, sharing)

(Notice that the Hotspot version string does not have the "fast debug" string in it.)

The same kind of build on linux looks like this:

# Java(TM) SE Runtime Environment (build 1.9.0-internal-fastdebug-201409030732.staffan.jdk9-hs-rt-b00)
# Java HotSpot(TM) Server VM (build 1.9.0-internal-fastdebug-201409030732.staffan.jdk9-hs-rt-b00, mixed mode)



For references, when building from the hotspot source folder the results are these (both have "fastdebug" in the version strings):

Windows:
# Java(TM) SE Runtime Environment (build 1.8.0_40-ea-fastdebug-b04)
# Java HotSpot(TM) 64-Bit Server VM (build 25.40-b10-internal-201409081453.staffan.hotspot-fastdebug, mixed mode)

Linux:
# Java(TM) SE Runtime Environment (build 1.8.0_40-ea-fastdebug-b04)
# Java HotSpot(TM) Server VM (build 25.40-b10-internal-201409081453.staffan.hotspot-fastdebug, mixed mode)