Pioneer HU made for Scion/Toyota Sub output question...

Toyota part # PT546-00100 Head unit made for Scion in my 2010 XD.

I have just finished installing my Crunch P500.2, 2 channel amp and 1-10" Kicker Comp (in sealed box) sub in my 2010 xd, but have not yet powered up. I've tried to search this site and many other car audio forums trying to get this answer CLEARLY answered:
If the 2 RCA subwoofer outputs from my HU are MONO (which the HU manual only states "Subwoofer output of this unit is monaural"), than can I use standard RCA cables, using BOTH of the outputs from the HU, go into the 2 RCA inputs to my amp, and be able to bridge the sub with both channels of the amp?
It seems to me that I SHOULD use a Y-adapter cable, like my amp manual says,....BUT....what I think is throwing me off is, the Y-adapter is pictured in the amp manual as the single connector comming from the source (my Pioneer PT546-00100 in this case) and the 2 (Y end) going into the 2 RCA inputs of the amp. I kinda think that I would want that cable the oposite way, or am I overthinking?
If Y-adapter IS the correct way, then I assume I just pick Left or Right and move on?
Can't wait to power up and tune, so hopeing to get a direct answer here.
Install took a while, ya know, to do it right and look that good!

 

Thanks for the quick reply. I knew I was overthinking it.

 

I like your quotes too!