You can purchase the Pioneer service disc and it comes with instructions, but for checking bandwidth issues you just need some test patterns, the required ones may be on the video essentials Laserdisc which crops up from time to time on ebay.

I'll do a bit of a writeup of what to do when I get a chance.
You may also want to get the service manual for your player, they are available online for $5 or so, then you could look at tapping the composite video signal before it enters the OSD chip and you might get a better picture.
The X9 and X0 are the only players I've seen that don't get smearing on CLV (the S9 still smears on some titles, like Top Gun for instance).

Your best bet is to adjust the player to be within spec and get the composite signal as early as possible. An outboard comb filter like the faroudja VS-50 can also make a huge difference, if you can find one.

Better still pick up a Pioneer LD-V8000 the most under rated lasedisc player ever, it gives a better picture than the Pioneer S9 and can be regularly found on ebay or at dealers for less than 50 bucks. Very very clean signal path and a great image, better than any of the 704, 703, CLD-97, 99, S9 etc. that all suffer from smearing.