When I get my 8i6 and have the time to test I will get back with the result. But I guess that Monkey_Man is right, but that both ways will work.
I'm sure it'll be doable, but I suspect the interface won't allow you to output guitar-level signals and the split feed from your geetar would therefore be line-level, which means you'd then best use the Aux input on the rear of your Kemper.
That's not an ideal situation 'cause you'll want to use it for reamping, and on top of this, plugging your guitar directly into the Kemper's front-panel input would mean that on those occasions when you don't end up reamping, your recorded signal (guitar->KPA Rig) is gonna be as pristine as possible.