Habaneros can take a lot of sun. The more the better, usually. If you keep it in a pot all season, it's worth the trouble to dig it into the ground a little bit. Say 10-15 cm deep, to help keep the pot itself (and the roots therein) from baking. Or just arrange for the pot to be mostly shaded while the plant itself gets loads of sun.
The bigger the pot, the bigger the plant, and therefore yield, too. Unless you mess things up with seriously high-nitrogen fertilizing for some reason, which will give you massive
vegetative growth but little else. OTOH, in your part of the world, it's probably unlikely you'll even be able to OD a Habanero on Nitrogen compounds, considering how much sun it'll get. Balance is key, as always. For a long outdoor season, I'd recommend the final "grown-up" pot should be at least 10 litres. Again, the bigger the pot, the bigger the plant. You can always repot it into something smaller and cut it down to bonsai proportions for the winter if you want. If everything works out ok and you give it a big enough pot, you can expect some few kg of crop (sheer guesswork this last one). A few kg of Habanero is enough for most people to last the winter.
A Finnish friend got around 12 kg of Naga Morich (aka Bhut Jolokia aka Ghost Pepper) last summer from one plant (in an "ebb & flood" type hydroponic system). He eats 3 dried pods at breakfast every day. He may be insane.
Don't plant it in the big one right away. I use yoghurt cups as a first home (just poke a few holes in the bottom and water via tray), then milk and juice cartons (comfy enough for chiles to grow from 15 to 45-ish cm tall, same hole-poking prep), and then into the big one. Habaneros don't really NEED all that much root space, but more soil keeps moisture for longer etc... And they will use as much as you give them. I've seen very impressive shots of Naga Morich roots that filled a 12 litre bucket of soil in one 4-month outdoor season. More roots than soil in the end.
Also, once the plant starts blossoming, you can start to slowly increase the amount of fertilizer. When it's blossoming and producing pods at full steam, even 5 times the recommended dose won't be a problem, it'll just make sure the plant has enough resources to keep growing and blossoming and ripening pods at the same time.