Yes, yes they are.
Not all the time, generally. It's more more common to see women wearing kimonos than men. They may worn on both formal on informal occasions. For instance weddings, graduations, some meetings, festivals, coming of age ceremonies (20 for women) and that kind of thing. Men will more commonly wear a casual type of kimono when relaxing at home. For weddings the bride may wear a Uchikake a long white gown with lots of silver and golden embroidary. Young men and women today often prefer the standard western marriage in a church though relgion has little to do with it.
Kimonos are generally not made-to-measure. You will never purchase a bespoke kimono - instead they're made in rough sizes and it's all the dressing and wearing of the kimono. Kimonos can be incredibly expensive - the hundred and even thousands of pounds or dollars. They can also be pretty cheap if they're designed for longuing around at home are made of cloth rather than silk. To wear a kimono - this most true for women - requires a special dressing technique. In some cases assitance made be required to help someone dress in their kimono. In Japan there are special evening classes for young women, so that they may learn how to put on a kimono by themselves. The hair is usually tied back when wearing a kimono. This is done with a hair clip type thing - it's important that this clip is elegant and not just any old thing grabbed from a draw.
One of the many favourite complaints of old people today - is that young Japanese women - no longer even know the complex operation required to put a kimono on, on their own. The nerve of those youngsters!
The Yukata is the informal kimono worn by men. The sleeves are quite short, all that's worn underneath is underwear. A man will usually wear sandels, if outside, with such a kimono - obviously inside the man wears no footwear - or indoor slippers. It's quite cool but the really cool man's kimono is the formal one. This comes in two parts the haori (a halfcoat) and hakama (a divided skirt). The Yukata is a tiny bit like a lightweight dressing gown - apart from it looks cooler and is often worn outside the house as well as in.