When does your trip occur, during your current Use Year or during next year's UY? The points you have available during that time period are the points you can use. If you need to bank, you'll have to bank first. If you need to borrow, it will ask you if you want to borrow.
If your trip is already booked, those points are taken out of the inventory, but they can be put back into the inventory if you cancel the trip.
On the Member website, when you log in as a member, go to My Vacation Points. If your points have not been used to make a reservation, they will show up as vacation points remaining. If they have been used, they will not show up. But you can check the reservation that was made using the points by checking View Vacation Details.