Depending which ultra you got, 512/128, you will get it for sure next week.
I'm trading in a note 10+, so I get $700 for my trade in using best buy or Samsung direct, that's the only reason I'm getting somewhere else then Verizon. You're getting $150 more for your s9+ then what best buy gives for it, so that's better deal. Only thing I'll point out is, Verizon trade in is in 24 monthly credits, it you want to pay it off next year you will lose the remaining credits, then really only got $225. Best buy and Samsung direct, the trade in is credited in full immediately. With best buy, the phone is also $50 cheaper then Verizon before trade in.
If you were at all interested in the s20+, best buy has a promo of $150 off in 24 credits, plus you still get there trade in up front.