I think a tripod is no more necessary than with other lenses. And perhaps less so due to the low subject magnification of the wide lens. Of course a tripod will help in any case! I have to admit not using a tripod for years, even with medium format, but then I don't use long lenses either... and the photos have often suffered a bit as a result.
I recently got a 21mm f/3.4 myself, and I have no expectation of using a tripod with it. But I use steadiness techniques and take advantage of any available support in low light... such as leaning against a wall for instance.
Suggest you just meter as you normally would. In-camera meters may be more difficult with such wide lenses due to including bright light sources that disproportionately affect the meter reading, so for scenics tipping the camera down a bit for the reading will exclude some of the bright sky for example.