I don't know about the XLs but IMO the T6s don't come close to the <= 10mm XWs in terms of enjoyment, due to superior comfort and contrast of the XW. Giving up 12 degrees of a huge FOV is a small price to pay for the privilege and of little consequence IMO; 70 degrees is heaps. T6 are nice and compact though, much more pocketable and also make better travellers than XWs. Every EP is a set of compromises. btw: the T6 is very different to the 14mm 4k uwa. Try before you buy.
Between the 9 and 10.5mm XL the biggest difference will be the focal length. What scope would they be for? What kind of observing?