1. **State the problem:** We need to find the volume of a cylindrical candle with radius $r$ cm and height 9 cm. 2. **Formula for volume of a cylinder:** The volume $V$ of a cylinder is given by the formula: $$V = \pi r^2 h$$ where $r$ is the radius and $h$ is the height. 3. **Substitute the given values:** Here, $h = 9$ cm, so: $$V = \pi r^2 \times 9$$ 4. **Simplify the expression:** $$V = 9\pi r^2$$ 5. **Interpretation:** This means the volume of each candle depends on the square of the radius multiplied by 9 and by $\pi$. **Final answer:** $$\boxed{V = 9\pi r^2}$$