Can you play Captivating Poke Puff if your opponent's Bench is full?
No. It's public knowledge that you can't put down any additional Basic Pokemon on your opponent's Bench, so you cannot play the card.
Source: TPCi Rules Team (2016-08-11), TPCi Rules Team (2017-08-03)

Relevant cards

Note: All applicable cards may not be listed below.
XY11_99