Silver
One of my favorite combinations.The ARC 1509 is my primary 9 wt. And my favorite line for it is the XLT 8/9. When I use sink tips (especially with wind) I use an XLT 9/10. IMHO, the original GrandSpey 8/9 was too heavy to reach much distance (although it was useable in heavy winds) — it greatly overloaded the rod. I have one of the new GS 8/9s that I haven't had a chance to try yet (our rivers here are solid). I'm looking forward to casting it. As a floating line, you'll be pleased with the XLT 8/9.
Bill