I didn't have quite as many Xs on my grid as your screenshot when I found the missing piece. My solution is all about realizing what is not on Monday.
#9 Neither Thursday nor geology is Monday, so X for Jaxson+Monday, X for Jaxon+bugling
#1 Neither woodshop nor Tuesday is Monday, so X for Valentina+Monday, X for Valentina+bugling, which means found Devon+Monday, found Devon+bugling, more Xs for those
#3 found Devon+home economics, found Thursday+orienteering, more Xs for those
#7 found art+Friday
#9 Thursday is not art, so found Thursday+Jaxson, found geology+art+Friday, found canoeing+Tuesday, found pottery+Wednesday, found Asia+Tuesday
#1 now that we know canoeing+Tuesday, found Valentina+woodshop+Wednesday, found Dorian+Friday, found science+Tuesday, found math+Thursday, done.