To solve math expressions we need to respect the order of operations. The first expressions we should solve are the ones inside parenthesis, then square brackets and finally the brackets. If there are more than one operations inside one of those we need to do multiplication / division first and then sums / subtractions.
With this in mind, let's solve the problem:
[tex]\begin{gathered} 9-\left\lbrace 5\lbrack4-(8+2\cdot-3\right)\rbrack-2\} \\ 9-\left\lbrace 5\lbrack4-(8-6\right)\rbrack-2\} \\ 9-\left\lbrace 5\lbrack4-2\rbrack-2\right\rbrace \\ 9-\left\lbrace 5\cdot2-2\right\rbrace \\ 9-\left\lbrace 10-2\right\rbrace \\ 9-\left\lbrace 8\right\rbrace \\ 9-8\text{ = 1} \end{gathered}[/tex]