I am in the process of replacing my front rotors and have been advised to use bearing mount adhesive (like Loctite 609 or 620) on the spindle and inner bearing. As I understand it the bearing and spindle surfaces that contact one another are to be clean and free of grease before applying this chemical and that this will essentially "lock" these two components together and prevent wear at these surfaces. Anyone have any experience with this?

I've never used anything but bearing grease in the front end. Never had any issues of wear on any other surfaces.

It's a split nut with allen cap bolt to lock it.
Even if you could clean it good enough to use loctite why would you?

Only two ways it can fail, you forget to tighten the allen bolt or you let the bearing fail so badly the whole spindle fails.
Even if you forget to tighten the allen bolt it will only get tighter, that's why one side is a left hand thread.

If your adviser is a mechanic I'd suggest you find a better mechanic.

If I'm reading this correctly the OP is talking about gluing the inner bearing to the spindle. I'm not sure what the point of that is, as the inner bearing race doesn't move if everything is correct, and so no wear is possible.

Would be a bear to do anyway. If the surfaces need to be grease-free, you'd need to pack the bearing with fresh grease, then scrupulously clean the inner race surface before putting the bearing into the hub, and then install the grease seal without getting any grease on the bearing race. I'm not seeing that as a happening thing, myself.

That's how I'm reading it too. Those compounds are typically used when wear loosens tolerances or things are machined incorrectly. Ive used them to augment press fits in spherical bearings before with good success. But you do not need to use them on spindle races.

we used to use green lock tight on a bycycle bottom bracket where the sealed bearings where held in by just circle clips and on headsets where the press fit races had become loose. No reason to use it on wheel bearings if the tolerances are correct. If they are not correct, either repair properly or replace.

I use Loctite 680 because the bearing housing was spinning on the spindle. Makes it a bit difficult to dismantle but cures the problem.

If the bearing has spun on the stub axle it may be a solution,otherwise don't do it....simple as that.
Remember to pack the new bearing properly and don't overload the grease in the hub,good luck.