I says "AES support in FS9 planned." on the product page.
That's not really restrictive, it's just to indicate that, since the FS9 version has static jetways, FS9 user can get animated ones using AES, that doesn't mean the FSX version is purposely made to not allow AES for it, it's just that AES seems to be more requested by FS9 users. And, btw, we'll have GSX in FSX...