Firstly, let’s establish if this week is already Halachically “Shovu’a shechol bo Tisha b’Ov”? or whether this only commences next Saturday nite?
Meanwhile bear in mind that observances of the 9 days, are deRabbonon, whereas “vNishmartem Me’od leNafshoseichem” is a Chiyuv miDeorraisso from next week’s Parsha of voEschanan, so you could even change the sheets on a Shabbos, so no-one gets infected, even if not sleeping until Saturday nite.