Does anybody have experience cooking in high elevation
Get a pressure cooker. This simplifies many things but especially beans/legumes. It's also handy for braises because your cooking times will get longer otherwise with the lower simmering temps. Consider pork shoulder or brisket where the finished temp is often 190-195, an artifact of breaking down collagen. Your boiling point is 194 at 9000 ft. So you will have some difficulty if you don't use a pressure cooker that will account for the lower pressure.
Baked goods can change a lot, but yeast based breads seem fairly consistent from what I've read. Your dough doubles faster so use a longer ferment and or less yeast. Humidity is often lower at that elevation so you'll have some liquid adjustments to make most likely.
Ask some chefs who work in the ski industry. They'll have some more experience. I've read a few articles in the past such as one chef who cooked at 10,000. Beans wouldn't cook at all without a pressure cooker.
I lived and cooked professionally at ski resorts for 10 years, yeah beans are out for regular methods, and don't do hollandaise, and cream (even manufacturing cream) has a tendency to break and don't try reheating it. For the most part it is not that different except baking.