They are not generally very flexible about the 1 day in office per week. If you are sick enough on that day, to possibly be contagious (only exemption for COVID), but not sick enough to (in my opinion) justify the use of a sick day, they will still make you come into the office. And not allow you to WFH, to keep everyone healthy. Even though all your meetings are virtual anyways.
Working hours are fairly strictly from 8-5. Some teams my differ, but that's the policy.