I don't have Justin's FS9 mesh, but his reputation is very good. If his mesh was made with the FS9 SDK's resample, it probably wouldn't work in CFS2.
As far as other LOD9 or LOD10 meshes, the question to ask is when was it made? If it was made before the SRTM data was available, it probably is not very accurate.
If you don't want accuracy, then you might as well just use the default mesh, LWMs and VTP1 lines. I could make LOD9 10 11 12 13... but if it is just fantasy, I'd rather not do it.
With SRTM, LOD9 is definitely pushing the limits. With mesh, more bumpiness doesn't mean it's better. And, if you're just hoping for prettier screenshots, then you'd be better off using FSX.
I've felt CFS2 was meant for combat, and LOD9 doesn't add much to the combat or navigational needs of the sim.
I only made the mesh because the simviation mesh that is so often mentioned is extremely flawed. The flaws were caused by the poor production of the mesh, not by the data used. My mesh doesn't have the same major flaws, so is useful for CFS2.
I have used my mesh is FS2004 and FSX. It works just fine, which just proves those products are backwardly compatible with the FS2000 SDK I used.
Dick