To simplify the expression \(-8x + 3y - x + 9\), we can combine like terms. The terms involving \(x\) are \(-8x\) and \(-x\):
\[ -8x - x = -9x \]
So, the expression can be rewritten as:
\[ -9x + 3y + 9 \]
Thus, the simplified expression is:
\[ -9x + 3y + 9 \]