If you bought it through Crutchfield it should come with all the wiring harnesses you need. Should be a simple plug the Alpine harness into the back of the HU, then the other end goes into the Crutchfield harness which then plugs into the factory harness. I'm assuming the 9835 is one of Alpine's Vdrive or whatever that claims high power output, hence the recommendation of the 10gauge. I had one of these in my previous vehicle and simply used the factory wiring harness and never had any problems.
If it's an XE like mine, I don't think there is an external factory amp so when you put the new HU in there it will be running off the new Alpine HU.

Don't know if that makes sense....

Here's a pic of my 9830 installed:


I couldn't get the Alpine supplied trim ring to fit.