You can leave it open, that hose is sort of "dead" in a sense that it does nothing when not connected. I would just tie it out of the way or something so it doesnt lay on the header or anything like that.
Try it out, i bet you dont get any grinding.
2012 F-150 XLT 4x4 EcoBeast SuperCrew
2007 F-150 XLT 4x4 5.4 SuperCrew - Leveling Kit - Magnaflow Cat Back - Tonneau cover - Traded
2004 F-150 4x4 S-Cab, 4.6, Auto, Edge Programmer - Traded
Everything You Wanted To Know About IWE's