The sequence $-3, 0, 9$ can be analyzed similarly to the previous one, but the inclusion of a negative number suggests a different pattern might be at play.

One possible interpretation is that the sequence is following a pattern where each term alternates between a change in sign and possibly a quadratic or arithmetic progression:

1. $-3$ (negative)
2. $0$ (separator or neutral point)
3. $9$ (positive)

Notice that from $-3$ to $9$, there's a change in sign and a jump of $12$ units (i.e., $9 - (-3) = 12$).

If we hypothesize the sequence continues by maintaining this pattern, we might:

• Reverse the sign again, so the next number might be negative.
• Continue the progression by subtracting $12$ from $9$.

Thus, the next number could be $9 - 12 = -3$.

However, since we already had $-3$ earlier, let's consider another approach.

If we look at the pattern of squares, the absolute values are:

• $\sqrt{9} = 3$ (with the negative sign)
• $0$ (neutral)
• $3^2 = 9$

Continuing with square numbers, the next square after $9$ is $16$, so the next number might be $16$, with no sign change needed since $0$