To determine the range of the given graph, we need to identify the set of all possible output values (i.e., the $y$-values) that the function takes on.

By observing the graph:

• The graph reaches a maximum $y$-value of approximately $9$.
• The lowest point (minimum $y$-value) appears to be around $-9$.
• The graph covers all values in between these points without any gaps.

Thus, the range of the function can be written as: $\boxed{[-9, 9]}$

Would you like further details or clarification on this? Here are some additional questions to deepen understanding:

1. What is the definition of the domain of a function, and how would you find it for this graph?
2. Can the range of a function ever be larger than its domain?
3. How would you express the range if the graph extended indefinitely in either direction?
4. How can you determine the range of a graph with vertical asymptotes?
5. How would the range change if the function were shifted up by 5 units?

Tip: Always inspect the highest and lowest points of a graph when determining the range!