Adding an octave harmony to your scales can really liven up your playing, and is used all the time by blues musicians.
You can either repeat the C at the bottom of the scale, or add the octave C above.
You will have to slightly adjust the fingering to what you’ve already learnt in order to do this. I tend to only add harmony to the first four notes of the scale underneath. However here is the fingering I would suggest for adding the octave harmony below for the full scale.
Here are the fingering suggestions for when adding the octave harmony above the minor blues scale.
Practice this scale with the octave harmony until it feels comfortable and you’ve got used to the fingering. Then you can start to play around with the rhythms. You can also use this technique up and down the octaves on your piano or keyboard, which sound extremely effective during improvisations.