Responses
If you are keeping up with the current material they are already acting like a couple. In the sense Yuuri is not denying he is Wolf's fiance and there is small stuff here n there. But if you are looking for if they were declared as a canon couple it's a 'no' because they want to cater other pairing as well.
By the way author has a clear bias towards Yuuri and Wolfram pairing.
Will Yuuru gonna end up with Wolfram in the end???