Yes you can run fs9 scenery in FSX with the same results as the planes but some will work with no problems some not work and will hav a million problems. A lot depends on how it was written most Gmax suff i good just like the planes. some stuff is impossable so i guess you will just have to do what I did put it in and see what you have then play with it if have to till it is acceptable I have found that removing the tree textures from Georender stuff helps you can remove just the tree BGLs and still have an airport. but this is just hit and miss.

some stuff I didn't have to d anythiung to and other even when tweaked wern't worth it. shalako