I got the impression from Paul that the Marantz universal players were a good platform for mods and that they had similar but not quite as much potential as the SA14. I am not sure if he has seen the 9500 specifically since it is relatively new but one advantage the 9500 has over all previous Marantz (including the SA14) is that it has a better/new DAC (the 4398 by Crystal; the other models used older Crystal dacs).
What kills me about the 9500 is that is best used with a monitor. It is critical for initial set up (e.g. to set the digital output on or off) but is also handy for more mundate tasks like putting a disk on repeat. Assuming that the modded 9500 sounds pretty darn close to the modded SA14, then I think the choice would boil down to whether you have an AV system or an audio-only system. When I started this journey I had a (2 channel) AV system now. Just recently, I separated them and my living room system is now audio only. Hence, the 9500 is less user friendly and an audio-only player like the SA14 makes more sense.
Do let us know if you learn more about the mod potential of the 9500.
If so then this is great news