The L009 is reknown for having iffy (to say the least) PoE support, both in and out.
See:
http://forum.mikrotik.com/t/l009-dont-like-it/180693/18
And:
http://forum.mikrotik.com/t/l009uigs-2haxd-in-no-passthrough-poe-again/171563/1
It seems that “by design” the L009 PoE out ONLY works if the L009 Is powered by DC jack.
The possible solution (actually work around) in your case could be a plain 48V splitter to extract the power and feed It to the DC jack.
No comment on the utter stupidity of the design and on the lack of proper documentation.