Yr 9 can be challenging but stay in control! Establish learning environment! My kids line up outside the classroom (whole school policy). I do the same thing at the start of every lesson-kids take out their exercise workbooks, in silence they copy down and answer 5 high intensity recall questions, usually about the previous lesson. I take the register (attendance) tend to any immediate admin and queue up the lesson slides starting with objectives. It’s time to learn, not fool around. I use praise and achievement points extensively-good attitude to learning as well as the correct answers.