Unfortunately the answer I'm going to have to give you is the old "how long is a piece of string" one.
Assuming you're coming direct from the States and not via another European country, then you will have to clear passport control/customs and at CDG those can sometimes be woefully understaffed and take ages, while other times you will have your choice of desks and sail through. The good thing is that the longer it takes, the more likely your luggage will already be off the plane and on the carousel. I'd allow slightly over an hour from getting off the plane to getting out the airport building, with a plus or minus of 25 minutes.
However as the first Magical Express coach doesn't leave CDG until 9am (assuming you're arriving at Terminal 2; there is a different schedule for Terminal 1), so there's a good chance you'll be on that one or the 9:20. Generally the coach takes the Autoroute (freeway) route to DLP, unlike the private car services which take the shorter back-roads route, which means it can get stuck in rush hour traffic - at best it will reach the first of the hotel drop-offs about 40 minutes from leaving the airport, but be prepared for it to take over an hour.
Unfortunately the Marvel hotel is currently the last one the coach drops off at (at least until the
Disneyland Hotel re-opens anyway). It'll stop at Newport Bay first (if there are guests staying there of course, otherwise it will skip stops) then Sequoia Lodge, Santa Fe, Cheyenne and Marvel/New York in that order. Each stop will probably add on another five minutes.
Then check in to the hotel, drop off your bags and walk through Disney Village to the park - at best I'd have you on Main Street by 10:30, at the very worst nearer midday.