Slow auto panning

I have been playing with the H9 tremolo pan algo and have a question.

Im mostly interested in the pan part and not so much the tremolo, although im not really sure about the difference.

What i want to do is have the left signal slowly pan from left to right while the right signal pan from right to left, at a slow rate.

Is this even possible in a guitar pedal? 

Imagine recording some layers of ambient synth in a daw. And to modulate each layer you can use an lfo or auto pan however you like, just to add slow and sublte changes.

As a guitar player im doing much looping with delays, ambient stuff so the idea is to create subtle changes in the stereo field. 

There seems to be hundreds of tremolo pedals (but these are effects, that drastically changes the sound because of the fast rate), but something as simple as a stereo pan pedal which can go at a really slow rate doesnt exist?

Now back to the Tremolo Pan preset on the H9, when using the slowest rate and a sine wave with witdh all the way up theres no sound from the left channel. Its being panned from the center to the right while the left is silent. I dont understand if it is a true stereo output why would this happen when set to the lowest rate? If i increase the rate sound is coming from both LR. Maybe it behaves more like a tremolo than a panner. Im not an expert so im not really sure what to expect or to say somethng is wrong. 

Anyways, if someone understands what im trying to accomplish please let me know if you have any ideas how to achieve this. Thanks.