coolant valve

 

A (the?) coolant valve needs to be replaced in my 2005 Prius.
  Of course, I am told the car has to be at the shop for 9
hours.  How long does this job actually take?  I don't want to
be unreasonable, but I highly suspect it doesn't take 9 hours,
and it will be most inconvenient to not have my car for that
long.

Thanks.
--
Jean B.