I attempted to play the Najdorf

This didn't quite turn out how I planned it. I guess I should prepare something against the Closed Sicilian:

Both sides made mistakes, but it is a blitz game.

@tpr Very insightful and detailed.

This Nc3 d4 line has become incredibly popular recently. I don't understand your urge to play a6 and b5.
Bg7 is an obvious blunder, instead Nbd7 was called for. You should check the lines and pick your favourite or just play 2... a6.
Normally you don't go a6-b5, but just play g6 and Bh6/Bg7.
After he blundered his queen, there is no commentary needed.

Again, if you find Qd4 sicilians uncomfortable, play 2... a6 against Nc3. If someone plays like this:
e4 c5
Nf3 d6
d4 cxd4
Qxd4,
You simply play Nc6 Bb5 Bd7 and in that line you should not have major issues.

#3 It seems contradictory to use a blitz game to discuss the subtleties of an opening.
Here is a more telling reference:

4 Qxd4 and 5 Qd2 violate opening principles.
White gives away a tempo.
5 Qd2 and 9 O-O-O invite 13...Bh6.
White can get away with losing a tempo.
White can also play Bronstein's 1 e4 e5 2 d4 exd4 3 Qxd4 Nc6 4 Qd2.
Black can get away with 1 e4 d5 2 exd5 Qxd5 3 Nc3 Qd6.
So it is all playable, but there is neither advantage nor pressure.
Black should be happy if white played this way.
There is no need to fear or avoid the variation.
It is hard to believe that 2...a6 would be superior to 2...d6.
8...g6 seems inconsequent.
If black wanted to play ...g6 he could have done that earlier, starting even at move 2.
If 9...Bg7 is wrong, that is a tell-tale that 8...g6 was not right.