I think your CD9 has a digital out, so I’d continue to leverage that as a transport and just buy a DAC. Would be helpful to know what sound characteristics are most important to you and what you’d most like to improve upon, but without that I’ll just mention a couple very different options in your price range that would likely bring significant across-the-board sonic improvements.
There’s a Bel Canto DAC2.7 on US Audio Mart for $1100, which is less than half the $2495 original retail. I had one of its predecessors in my system and it was really sublime digital. Smooth but detailed with good tone and excellent soundstage. Read the reviews — Bel Canto builds great DACs.
Not used, but the new Soekris dac2541 ($1299) utilizes R2R technology, which tends to have a very natural and “analog” sound, and also offers several filters so you can custom tailor it toward your own preferences. Without knowing more about your sonic preferences and goals that’s all I got for now, but hope it helps a little and best of luck.