YVR is positioning itself to be a hub-centric airport, so it's in their best interests to ensure a smooth and efficient connection process for yourselves and your bags. Given that you're flying on a single airline on both legs, the process should be streamlined, and an hour sufficient. I assume you arrive at roughly 10:30am (between the Australia/Hawaii bank but prior to the main Asia influx), so you might time it nicely. AC's flight to Seoul leaves at noon at this time of year.
Being a US citizen will not slow you down at all.