Not that I'm aware of. I suppose you could try to convert another manufacturers larger aftermarket pad to the smaller size of the RO90, but you wouldn't have the holes line up and so sacrifice DC:https://www.woodworkingshop.com/search.aspx?q=interface
The stability of the pads totally depends on use and material. What really breaks the pads down is if you are using them with the sander in gear driven mode on inside (concave) curves or on any contoured shapes that are close to a sharp corner where the pad can catch. The pad life can be extended if you operate in RO mode -- it will just take a bit longer to sand the piece.
I have not seen any 3rd party consumables for the RO90. As far as I know the RO90 is the only sander in the entire industry that uses this format, and because of that it's probably not interesting for other brands but Festool to make consumables for the RO90.
The resulting high cost of operating this particular sander made me get rid of mine, though it is a very fine sander by itself.