Answer
$4088$.
Work Step by Step
The sum of a geometric sequence until $n$ can be obtained by the formula $S_n=a_1(\frac{1-r^n}{1-r})$ where $a_1$ is the first term and $r$ is the common ratio.
Here $a_1=8,r=2,n=9$
Hence here the sum is: $S_n=8(\frac{1-2^9}{1-2})=4088$.
