The chart below (click here for a larger version) will give you a general idea of what is covered at each level of Mechanics Instruction that Sticks. Notice that many of the units overlap from grade level to grade level. The Level A and Level B book focuses more heavily on punctuation and usage, the Level C book emphasizes punctuation and clarity, and the Level D book concentrates on clarity and precision.
I used the grade level expectations provided by the Common Core Standards (Language Progressive Skills by Grade) to make some determinations about unit alignment. Their grade level standards assume mastery of most of the punctuation and usage rules prior to middle school; however, my experience suggests that most ninth grade students still need direct instruction (often times very explicit instruction) in these areas.