No. 9 works well when combined with No. 8 as a study in basic articulations (slurred and tongued) over the middle part of our range.  One challenge with No. 9 is making sure that we hear the difference between slurred and tongued  without cheating any of the non-staccato notes.  For example, one tendency in measure 9 – and in similar passages – is to cut the third note in each group of four short in order to prepare for the fourth note, which is marked staccato.  Try as much as possible to give that third note full value.  Successfully playing measures 12-13 is really more about airspeed and less about tensing up the embouchure.  Recommended tempo is quarter=92-100.  Giusto means strict, appropriate, or proper.