Though it isn't the most appropriate response (stalling because you will lose) your opponent has every right to use the time allotted in the match. oftentimes I am called away during matches where i am going anywhere from 1-5 minutes. Usually I'll say be right back etc. but sometimes I don't make it back in time. I remember losing to Inigomontoya just from wasting my move times by chatting with him in the window.
There is no written rule that you have to play each move out swiftly but it certainly makes the game more enjoyable if both parties do. I could see where having an opponent stall out on turn 9 would be very frustrating but still within the framework of the game.
Nought's had, all's spent, Where our desire is got without content;'Tis safer to be that which we destroy Than by destruction dwell in doubtful joy.