1. **State the problem:** Find the coefficient of $x^9$ in the expansion of $(2x + 3)^6$. 2. **Recall the binomial expansion formula:** $$ (a + b)^n = \sum_{k=0}^n \binom{n}{k} a^k b^{n-k} $$ where $\binom{n}{k}$ is the binomial coefficient. 3. **Apply the formula to $(2x + 3)^6$:** $$ (2x + 3)^6 = \sum_{k=0}^6 \binom{6}{k} (2x)^k 3^{6-k} = \sum_{k=0}^6 \binom{6}{k} 2^k x^k 3^{6-k} $$ 4. **Identify the term with $x^9$:** The power of $x$ in each term is $k$. Since $k$ goes from 0 to 6, the highest power of $x$ is 6. 5. **Conclusion:** There is no term with $x^9$ in the expansion because the maximum power of $x$ is 6. **Final answer:** The coefficient of $x^9$ is $0$ because $x^9$ does not appear in the expansion.