Alright, this one is deceptively simple. A nice slow 12 bar blues to get your teeth into except there are a few jazzy additions in here like chord substitutions and ii, V, i turnarounds.
Here are some scale choices for you over the 7 chords:
Minor Pentatonic Major PentatonicMixolydianBlues Half / Whole diminished ( 1/2 Diminished Scale )
Over the minor chords:
Minor PentatonicBlues scaleDorian PhrygianAeolian (natural minor)
Over the Bbdim7:
Just keep it simple and try out the Bb diminished scale, just step up in minor thirds. Remember you can also outline the chord shapes. This is a really good way to start moving between the chords and making sure that what you play sounds great. Try making the chord tones the ones you hold for longer and use other notes from the scales as passing tones. This way you can always be sure what you play will sound great.