Well, yes. These are some intermediate format. They export these from 3DS max or Maya, and then convert them to .nsbmd by using another tool.
Considering Nintendo's tools, and also Nintendo's own specs for the file formats are both leaked, one .imd file won't help much

Still it's a nice find. It's weird that you found a .imd in a game, these can't be used directly by Nintendo's libraries, so it's most likely included by accident and not used by the game...

 

Dirbaio mentioned it in passing but to make it clear a couple of years back the part of the DS SDK that does 3d files got leaked- it included plugins for old versions of maya, 3d studio max and one other that changed a nice in the subsequent years to spit out imd files, a converter for the files to NSBMD and a minor set of editing tools to allow people to edit the odd colour and lighting to save having to reconvert (not that useful) as well as a few PDF documents detailing the 3d system from the game programmer perspective (nothing that gbatek and a reading of the NSBMD format will not tell you and if you read those you will have far more than the PDF documents ever told you).

A handful of the guides you might see about the place to handle NSBMD hacking (mainly for NSMB and Mario kart when I went looking) even make use of them but sharing such a program is discouraged around here so not as much discussion tends to happen as you might imagine.

Now it might still be useful as 2009 is probably a later game/SDK version than I reckon the leaked version we have is from but any changes to the NSBMD format are few and far between- nothing close to the NFTR or even the few minor things SDAT had although what we might have seen as a shortcoming of a tool could have been a change I guess. Worse is I believe the 3d stuff is from a far later version of the SDK than the complete SDK that did get leaked so it is not even that useful there (although as mentioned it can act somewhat standalone so it is not so bad). One of my many started threads that I did not follow up on did include a discussion on the versions/deviations from formats-
http://gbatemp.net/threads/deviations-from-the-nitrosdk-formats-maybe-versions-thereof.329645/