Microcontroller Vol Maximum Voltage compatibility
The \$V_{oh}\$ and \$V_{ol}\$ specs you're referring to on page 31 of the datasheet aren't really specs on what output voltage the chip will provide. They're test conditions for the \$I_{oh}\$ and \$I_{ol}\$ specs.
The spec is saying, for example, if you externally force the output pin to +0.8 V when the chip is outputting low, the chip is guaranteed to sink at least 5 mA.
Since you don't have to sink any current at all to keep your transistor base below threshold, the outputs in your circuit will certainly achieve a lower output voltage than 0.8 V. In fact, since in your circuit the micro doesn't have to sink any current at all to pull the transistor base low (\$R_B\$ takes care of that), you should achieve very close to 0 V, and you should have no trouble turning the transistor fully off.