The author writes about an app (Helium) which can be reused to make the N9 act as an DLNA player (not server). He says there's a call to a method? that provides a URL for the media the client should play. Maybe there's an easy way to fill this gap.
No, there is no DLNA player on the N9, unfortunately. The both mentioned apps are DLNA controllers, very nice that they exist, but unfortunately without playlist queue (@phako, wink wink :-)