Yes, you can.
For a domestic adoption, if you pay qualifying expenses in any year before the year that the adoption is finalized, you can claim the credit in the year after the year of the payment.
See When To Take the Credit or Exclusion in the Instructions for Form 8839 for more information.
As far as the name to enter, if you actually did adopt a child, go ahead and enter his or her name and identifying number, even though you wouldn't have known this information at the time.
On Form 1040-X, Amended U.S. Individual Income Tax Return, you'll have the opportunity to explain that the adoption wasn't finalized that year, but you incurred these expenses in 2017.
If there is any carryover credit, or you also claimed the credit in a later year, you may need to amend subsequent year returns, as well.
