My temporary veneers are coming out one after another. Do I have to get them reattached or can I wait until perms are in?

Some veneer cases are very minimal in prep, so likely won't matter in 9 days.  But if the preps "broke contact" (meaning enamel removed between the teeth), then the temps were holding space.  Without the temporaries, the teeth may/can move, making the appointment to bond the permanent veneers difficult or impossible.  I suggest seeing your dentist asap to have them help.

It is important to have your temporaries put back on your teeth as soon as possible.  Without them, you run the risk of fracturing your teeth, or having excessive movement.  Teeth are always moving, and if the temporary is not there to hold the position, your teeth may move and not allow your permanents to fit properly.  

The answer to your question depends on how your teeth were prepared for the veneers. If there are small spaces that were created between your teeth, they may close slightly which might affect how the veneers fit. The edges of your teeth may be thinner which can chip more easily, which can then affect how the veneers fit. In terms of brushing, it's not a problem to brush them. You won't affect the outcome by brushing. I would suggest speaking to your dentist. He/she would have the best knowledge about your situation. I hope this helps!