Choice A is the correct answer.

1. Set $y = 0$: $x^2 - 9 = 0$.
2. Factor as difference of squares: $(x - 3)(x + 3) = 0$.
3. Solve: $x = 3$ and $x = -3$.

The intercepts are $(3, 0)$ and $(-3, 0)$.

Choice B is incorrect because it misses the negative and is the wrong value. Choice C is incorrect because it is the y-intercept. Choice D is incorrect because it forgets the square root.