Nobody has ever reported this problem before. However, you can try using the Texture Resizer available in this forum, which will decrease memory requirements for textures, and should speed up loading.
The issue is, the scenery has been made for FSX and then back-ported to FS9, and FS9 can't load textures in the background using multithreading and additional cores so, it contains an amount of textures that FSX can handle without any issues on modern cpu, but FS9 can't, even if you *have* a modern cpu. So, the available textures resizer can help.