It all depends on how much extra room you have inside your hard drive caddy for your particular system. Thinking off the top of my head, there would definitely be some modification necessary to the HD caddy for this to work on a 9300 since it fits lengthwise almost exactly in the caddy. Also, hopefully the width of that adapter isn't wider than a 2.5 HDD because those fit widthwise almost exactly in the caddy as well. Even with modifications, I'm pretty sure the caddy would still barely extend from the system, in which case you would need to secure it somehow.
If you truly want to use a SATA HD you should either buy a SATA 9300 mobo or buy a secondary HDD caddy from ebay that is SATA. The secondary caddy would take the place of your dvd drive but you can always use an external dvd drive.