Usually the students would take SAT in May or June of Grade 11 (or one year prior to the final year). If needed, take a re-sit in October or November of Grade 12 (or the final year).It is not recommended that a student takes SAT for more than 3 times. It is also inadvisable to take the SAT earlier because you have to compete with those who learn for a longer period than you.
As far as I know, not most students would take tuition on SAT. However, you need to practice on your own whether or not you take tuition on SAT. Just buy two to three workbooks and complete them before the test.
Usually, the students would practice the SAT during the summer vacation of Grade 10. They will continue the practice until they take the first SAT test in May or June in Grade 11.