Rush hour traffic Toronto?

Allow at least 2.5 hours - ie, around 6:30 or so, depending on where in Barrie you're coming from. It's not usually that long (it'll probably take about an hour and a half to 2 hours) but you never know when somebody will roll their car on the 400/401 ramps. You're going with the rush and will hit it at the worst time. It is a miserable drive, but some people (possibly insane) do it every day.

Alternatively, there is a GO train that leaves Barrie at 6:50AM, arrives at Union at 8:20, and then take the subway back up to Yonge and Lawrence, arriving somewhat before 9. You could actually take the 7:20 train but the timing would be tight especially if you don't know where you're going. The train takes a bit longer than driving but is much more reliable and much less stressful than driving.

On average it takes 45 mins to get from Barrie to 400 @the 401, from there it would take a good 20 mins. Thats just over an hour in non rush hour. Barrie to Toronto (yonge/lawerence) would take 70-90mins depending. Your appt is at 9:30am, you should leave no later then 7am.

I suggest you leave at about 5:45.

It's bad