We will be taking our almost 2 year old son on ME this fall. Can a car seat be installed on the bus? I am not sure how comfortable I am with him in a bus with no car seat installed. Would it be better/ quicker just to take a taxi? Any experiences/ thoughts appreciated.
The major point for you to realize is that if you are uncomfortable with your 2 year old on a bus without a car seat, then your only option is to rent a car at the airport. Disney Transport buses, the buses that take you between the resorts and the parks, also do not have seat belts (and thus car seats aren't permitted because they can't be secured).
Of course, if you are staying in a monorail resort and will go ONLY to MK and Epcot, then you won't need to take any buses. Since that's unlikely, plan on either renting a car and using your car seat, or getting used to the idea of riding buses with your 2 year old.
Another option would be hiring taxis or a car service to drive you everywhere, but of course that would be incredibly expensive.
Just for some personal info, my wife and I have no problem taking our kids on buses. Our first time with them at WDW, they were 2.5 and 5. We take safety VERY seriously, as in each of our jobs we see the devastating effects of motor vehicle accidents every day. And again, given what we know, we are completely confident taking our kids on buses not equipped with seatbelts, whether it be in WDW or in Manhattan or on school field trips.
We also have lots of experience being around buses, as Atlantic City has many more motorcoaches going in and out and around town than WDW has. Buses are a way of life around here.