Question: I lived in Canada for 7 years until grade 5, then I went back to Taiwan and came back in grade 9. Do I need to take the TOEFL?
If the primary language of instruction during your high school years is English, then colleges will usually not expect you to submit a TOEFL score. BUT ... occasionally colleges want a TOEFL score from any applicant whose first language (the one spoken at home) isn't English.
So ... if your first language isn't English, be sure to read application instructions carefully. They will vary from one institution to the next. If a college does expect a TOEFL result from all non-native speakers, you can write to admission officials and explain your situation. Since you have spent so many years at school in Canada, they are likely to waive the TOEFL requirement. You should also take the SAT (or ACT) before you contact colleges. If your reading school is good, then that will give you more "ammunition" if you are requesting exemption from the TOEFL.