I have The Academy and play Meditation as my first spell of the turn. What is the maximum number of cards I can draw?

Three. If the optional additional cost is paid on finalization and the spell repeats, you draw 2 on the first execution and 1 on the repeated execution. The "exhaust a unit; if you do, draw 2" lines are linked; "Otherwise, draw 1" is not linked to that payment, so on the repeat you did not pay the cost and only the otherwise branch can apply.