Turn off circuit using microcontroller signal
Max current through Q4 would be approximately \$\frac{9V}{10k} = 0.9mA\$, which is perfectly fine. 

As pointed above, that 200R base resistor could cause problems, \$\frac{(5v-0.7v)^2}{200}=92mW\$, that's more than a small chip resistor can handle. In any case it's safe to assume that the transistor has current multiplication of at least 10 so it'd be enough to supply 90µA. In practise, use the same 10k resistor as you have in series with the transistor..