If \( \displaystyle \sum_{r=1}^{9} \left( \frac{r+3}{2^{r}} \right) \, {}^{.9}C_{r} = \alpha \left( \frac{3}{2} \right)^{9} - \beta \), \( \alpha , \beta \in \) \(\mathbb{R}\) , then \( (\alpha + \beta)^{2} \) is equal to:
\(81\)
\(27\)
\(9\)
\(18\)