Honestly, it seems to me that the carry on might not be your issue. On that score, quite honestly, keep your items to the minimum. Even now, the less you carry, the quicker you'll get through.
I'd just want to confirm the logistics of managing a 90-minute connection. I confess that I've never done this through Pearson.
But I've started my travels through Pearson, and these days it ain't pretty. DSIL flew to Dallas last week, and from the moment she took her shoes off, to the point where she'd got them back on (and after she'd been through the full body scanner, and the staff had inspected every single pocket of her purse and opened her lipstick - honest) it took slightly more than 30 minutes. She arrived at the airport three hours before departure, and said she'd do exactly that again. This was for a mid-day departure.
When we start at Pearson, the routine has usually been:
Check in to get bag tags ('cause we already have boarding passes, so heaven only knows why it takes so long) - 30 minutes
U.S. pre-clearance: 20 minutes
Security: 10 minutes
This has changed substantially, of course, since late December. A DF travels weekly to the U.S., and he's arriving at ridiculous hours to ensure he gets through in time to make the flight, to make his meetings.