As a single Blazers game performance, Lillard's last night was the best I've ever witnessed when you consider the stakes and the magnitude of it all.
But your question is specifically about the shot, and it has to go to ".9"
It exorcised the 14-year demon of failing to get past the first round. And like you, I also thought we had lost that game, so when the .9 prayer left Dame's fingers, I didn't expect it to swish; my surprise and shock were absolutely off the charts, which were then followed by extreme jubilation and exhilaration. Additionally, if Dame misses the .9 shot, we lose the game and go back Houston for a Game 7, where the Rockets would be the favorite to win the game, and therefore the series.
Not to take anything away from it, but yesterday's game was tied when Dame made the buzzer beater, so even if he missed the shot, Portland would still have a chance to come away with a victory. And even if we lost last night, there was still one more home game to clinch the series for the Blazers. So the urgency last night doesn't quite compare to the shot against Houston, IMHO.
Also, when the shot went up last night, I knew there was a chance it would go in because Dame has proven his clutchness over and over in his career by now. But for the .9 shot, even after it left Dame's hands I was pissed because I knew it wasn't going in (until it did!). At that point in time against the Rockets, though Lillard had hit a few game-winners already in regular season games, his clutchness was still unproven in the Playoffs.
Not to mention the fact that the .9 shot was off a broken play. LMA was the # 1 option in that last set, and Lillard didn't really expect to shoot the last shot. The fact that he had the presence of mind to break away from the play that was called and then to get the shot off in less than a second with a taller player in his grill added to the epicness of that shot!
That's why I think ".9" is the bigger shot and it's not even really close.