Greg,
I got my 798Ci SI HD in March 2012. I bought it with the portable case conversion kit so I could use it with my canoe. I used it all summer and it worked great.....lots of fun. Now its time for ice fishing and I had the same question about the XI-9-20 being compatible. Your response answered my question. I plan to place my order tomorrow.
Thanks,
Charlie,
Bethlehem, PA