The expression to simplify is:

$- |9|$

Here, the absolute value symbol, $| \cdot |$, makes any number inside it positive. Therefore:

$|9| = 9$

Now, applying the negative sign in front of the absolute value:

$- |9| = -9$

Thus, the simplified result is:

$-9$

Would you like more details or have any questions?

Here are 5 related questions:

1. What is the absolute value of $-9$?
2. How do absolute value and negative signs interact?
3. Can you simplify $-| -5 |$?
4. What happens when you have $+ | -7 |$?
5. How does the absolute value function affect real numbers in equations?

Tip: Always handle absolute values first before applying any other operations like negatives or addition!