I think it would depend on how much yeast, size of bottle, etc.
I like to put a bottle up in a plastic water bottle and then feel how hard it gets. If it starts to blow out the bottom and is rock hard within a couple days, I think you will need to pasteurize.
You can simply run your bottles through the dishwasher on normal cycle (no soap obviously) if you want to stop the bottle conditioning.
If you don't want to do that, just keep in the fridge.
My guess is with that SG and using Stevia you would be fine cold crashing it for sure. Or you can simply store your plastic bottle near you glass bottles and monitor it daily, etc.