The whole music during the 3 weeks thing is a minhag to show aveilus. Some even listen to recorded music. The point is not to be happy. Music that might cause you to dance is the real issur. Elevator music does not fall into this category. Perhaps we shouldn’t go in elevators all year because they might play goyish music!
From what I heard, it is completely mutar to shower, wear clean clothes and shave for a date during the 9 days if it necessary for occasion (first date, etc)