the Uber XL is only required to fix 6 people. The list of acceptable cars includes Highlanders and Pilot's so... that would be a crap shoot to weather you would get a 8 passenger vehicle or not.
You can get fare estimates on Uber’s website. If you’re a first find user, you can probably find and use a promo code.
You can check out some car services too like Tony Hinds, Tiffany Town Cars, Happy Limo or Sunstate
With luggage you’d probably have to take 2 cars no matter what. We find uber about half a normal taxi so you’d probably come out ahead even with 2 Uber’s. You can do a fare estimate by plugging in all the info like you were ordering one now- it’s just an estimate though and will vary based on time you get it and demand.