score:2
I'm currently on a J-1 visitor visa in the US, and we have similar rules. When I travelled from Canada, we were told to make sure that we got in on the J-1 and that the border agent didn't admit us on a tourist visa. With regards, to entering early or if you got admitted on the wrong visa, we were told that we would normally have to exit the country and enter again..
Alternatively, you may be able to schedule an appointment at the US Customs and Border Protection Deferred Inspection office and get your visa changed there, thereby entering on a tourist visa at first and then getting it changed to an exchange visa when possible. You should be able to schedule an appointment on this website. This is important to do since they will update your I-94 form.
This should apply to the J-1 type visa but its best to make sure about this from a more concrete source as well. If in doubt, I'd go with what the US officials say.
Upvote:0
Yes, visa waiver and then going to Canada to change to Exchange visitor should be possible. Another, and more official, way (but with much more red tape) is for you to apply for a tourist visa. Declare your intention, and make sure the consulate puts an annotation on the visa (I think they usually use "prospective student"). Then once you arrive in the USA, apply for a change of status (with the help of the university). There is a big pitfall here because the change of status can take months to process, and you would not be allowed to start your exchange program until that is approved.