$$a+\sqrt{a}=8\Rightarrow \sqrt{a}(\sqrt{a}+1)=8$$
$9a+a\sqrt{a}=a(\sqrt{a}+9)$
$\hspace {2cm}$$=\sqrt{a}\sqrt{a}(\sqrt{a}+1+8)$
$\hspace {2cm}$$=\sqrt{a}\sqrt{a}(\sqrt{a}+1)+8\sqrt{a}\sqrt{a}$
$\hspace {2cm}$$=8\sqrt{a}+8\sqrt{a}\sqrt{a}$
$\hspace {2cm}$$=8\sqrt{a}(1+\sqrt{a})=8.8=64$