There is a lot of conflicting information, and it doesn't help that every bariatric clinic has a slightly different take on things. The bottom line is that we each respond to food depending on our individual biology and primarily the make-up of our microbiome. It can take a little experimentation to find the right combination of foods that keep you satiated and energetic. Choosing the right foods are more important than tracking stuff, but tracking works well for some people, but it wasn't for me.
As far as cravings, I don't think it's wrong to enjoy something once in a while. I think it is part of the learning process of being able to eat normally without going overboard. Obviously, you have to control the urge to keep eating more, but I've worked hard on not feeling guilty if I have a guilty pleasure once in a while. That being said, most of the time I reach for one or two of my "go-to" snacks which are usually carrots and hummus, or an apple, or grapes, or some nuts. Sometimes I'll choose something not sweet even when I'm craving something sweet and that ends up doing the job.
Sometimes when I want something sweet I'll have some tea or coffee with a bit of stevia sweetener. Sometimes some fairly dark chocolate with just a bit of sweetness.
The other thing I do anytime I feel a craving is I drink extra water or a lightly sweetened fruit essence water.
If you are having sugar cravings periodically, you might keep a log for a while just tracking how you feel after meals. If you get hungry or crave sugar and/or get lethargic/bored a couple of hours after a meal, that probably isn't a meal you want to eat regularly. Conversely, if you have a meal that satiates you for 3-4 hours, keeps you fairly energetic, and doesn't trigger cravings, that's a meal you may want to have more often.
Consider adding a very wide diversity of plants to your meals. You don't need to be a vegetarian, and they don't have to be in large amounts, but the more types of fiber your gut bugs have the chew on, the more likely it is that you'll have more sustainable satiation and other benefits. I try to have 20-30 different plants each week. That may seem like a lot, but it includes anything that grows, nuts, seeds, grains (unprocessed), vegetables, fungus, fruits, etc.
Of course, what works for me may not be exactly what works for you, but consider branching out and adding things into your diet that perhaps you haven't thought of before. Diversity of food can really go a long way in promoting gut and body health and feeling satisfied.
I have reached way outside of my food comfort zone and found I like so many things I thought I wouldn't. It's made my post-op relationship with food so much better and more enjoyable than the junk I was eating pre-surgery.
As far as exercise and stalls. Exercise does very little with regard to weight loss. It has amazing health benefits, but actually triggering weight loss isn't one of them. Depending on your level of exercise, you may or may not need to adjust your calorie intake up a bit. If you are just adding some moderate exercise, it's probably not too critical that you add calories, although if you are 9 mos out and only eating 800 calories, that is pretty low. You'd want to add some if you are going to exercise regularly.
There's no magic bullet with stalls. There are lots of things that you can be trying, like others have suggested, adjusting calories, having a high-calorie day and then reducing back down, mixing up your food intake, etc. If/when the stall breaks, it probably won't actually be a result of a specific action, but a combination of things that led your biology to trigger some more loss. It doesn't hurt to try some things, but it almost always come back to finding the right foods and food amounts that make your body more efficient.
Finally, my disclaimer...these are the things I've done over the last year and a half to reach my goals and maintain them. Will this sustain me long-term? Only time will tell, but what works for me is my story...so take any advice you get from anyone, including me, with a grain of salt. Each person has to find the right thing for themselves, and of course, as always, don't make any massive changes to diet or exercise without consulting your physician.