Answer
The answers are:
\begin{align}
9a^3: &\color{red}{\text{Coefficient is 9 and Degree is 3}}\\
-4a^2: &\color{red}{\text{Coefficient is -4 and Degree is 2}}
\end{align}
Work Step by Step
To determine the coefficient of a term, identify the part of the term which is the constant factor (usually a number).
To determine the degree of a monomial, identify the number of variable factors in the monomial.
\begin{align}
9a^3: &\color{red}{\text{Coefficient is 9 and Degree is 3}}\\
-4a^2: &\color{red}{\text{Coefficient is -4 and Degree is 2}}
\end{align}