Hi Alain!
We're all waiting, indeed. According to the weekly webinars we hold with University's authorities, though, classes will be hybrid. This means that the same course will most likely be taught online as well as in person. Therefore, in case we don't arrive to the US in time, we will still be able to join the classes we've been following online.
Given that I took a gap year as well, I have no interest in deferring. However, I understand it is something that may happen if the visa situation doesn't move in the near term. At my university, we can wait until August 1st before deciding whether to defer.
I have been reading updates from a handful of schools and some of them are having full in person semesters, others full online, and others hybrid ones. I don't believe any of them will actually delay their start date.
I hope we remain patient during these times (: Best of luck.
P.S.: I just remembered the admissions office team at my U mentioned that there will be flexibility regarding arrival dates to the US, given the situation. I guess that means that missing a week or two of classes is possible.