I just looked at your dates on the wdw website under FL Res just to see what I could find, and if you put in each individual date by date the MK View rooms are available every night BUT it is
not available on the night of 9/8, when the only availability online for that one night is Garden Wing Deluxe - so I think that one night that the MK view is unavailable is skewing your whole stay.

I do know that if one night a view/category is unavailable during your stay it will show as all unavailable....
If you call them, you might also ask them if they also show that is the case for 9/8 (have them check each date). If so, you might have to get
very creative to get the MK view - i.e., one way would be that you might have to book MK View for 9/6 & 9/7 since it's available for those dates, then have a separate ressie for 9/8 at whatever is available (and then keep calling to try and get any MK View cancellation that shows up), then another ressie for MK View 9/9 to 9/11. But that also means that you might have to switch rooms 3 times (!) Wouldn't bother me, but my DH would probably choke me!), 3 deposits,etc. but you would know at least two of the ressies would be MK View! Or other plans like this. Then if the 8th would open up, you would at least be able to try and get the front desk to leave you in the same room for all dates
Sounds like mucho trouble but I guess it depends on how much you really,really want the MK view for all your dates!
If you really want the MK view, you should probably book it for any nights available asap, only because another date in your stay besides the 9/8 might lose availability soon due to popularity

....