I am thinking those numbers on the tires are for 'Sustained' weight. The frame will be fine and can handle those weights.
If you have one of those Infra-red temperature hand held guns you can check the temperature of the tires to be sure they do not overheat. Harbor Freight sells them cheap. I think anything over say 200 degrees Fahrenheit and the tire is too hot and would need more air but you should not go over the maximum rated pressure.
I dont think the tires are going to be the main issue.
At those weights the back of the bike may bottom out on a bump or pothole.
The front forks with stock springs are going to nose dive and bottom out during hard braking.
Are you running 'Stock' suspension? There is a Progressive Shock/spring setup made for the rear suspension which would fix that part.
New front Sonic 1.2 's springs and heavier weight fork oil would fix the front.
For now you need to screw in the front fork preload adjusters all the way and put the maximum air pressure in the back shock. I think it is 50psi max.
Just do not go fast yet.
This is more of a how to ride with a passenger and what to watch out for.
My wife and I have done a lot of 2-up riding over the years. Combined, we are at about 400 lbs unless she brings her purse and we are about 500 lbs. I run 15w oil with 5" cut springs in the front and "heavy" fluid in the shock and it is set on "3". The tires are 40 lbs in front and 42 lbs in the rear. One bike has radials and the other has bias ply (that handles way better). My wife likes the stock seat over the Corbin so I switch it when we ride together. Your stopping distance WILL be greatly increased with added weight. Try to do any hard stopping in a straight line as much as possible to scrub off speed. A good solo practice drill is to find a large quiet parking lot and practice panic stops by using only the front brake from second gear speed over and over to get used to where the point is just as the front tire skids and slides (in a straight line). What you are trying to learn is the feel of it and not so much the actual distance (as this will be greater when 2-up). This is a drill everyone should practice and learn for any bike they own. After you get used to it, it will probably be second nature and you will feel more comfortable with your bike. You can add a "little" rear brake and shorten the distance a "little" more but your front does mostly 80% or more of the actual stopping power. As with anything, if you are not comfortable doing it - don't do it as the end results can be tragic or at least severe damage to your bike. In our weight range I have never had any issues with the bike from a mechanical stand point what so ever other than an occasional bottom out or close to bottom.
I'm glad I know where the braking limit pretty much is because on a few occasions I've had to use most of it up or at least had the option of altering my course a little knowing things may not add up before I could fully stop.
Ironically, the worst issues I've had are the low speed parking lot stuff. My wife had a habit of moving around a little just as we would almost come to a stop in a parking space. I have to remind her to not do this on occasion. You can pull a thigh or groin muscle pretty easy try to hold the bike and both of you up as it is trying to go over.
The other thing to watch out for is driveway entrances to businesses off a main road (like when you pull into a gas station). It is quite easy to bottom out as these are usually made to help keep water draining so they also serve as a gutter. Watch your speed and angle on them so you don't bottom out.
Another is the left turn transition from one road to another. There is quite often a hidden dip or hump for water drainage that can cause you to scrape a peg in the turn when you are not expecting it. They can be anywhere but usually are on the edges of the travel lanes to include the edge between two lanes where the dotted line is.
Good luck and be safe out there!