1. Some flights swap between terminal 8 and 9 daily. Your flight does not require to be in T8 (international arrivals) as MIA-JFK .. so there is a 40/60% chance of where it really will go. Monitor the flight for a few days and I'll be it changes location. UNLESS it becomes an international outbound . but that is not 100% either.

I flew BDA-JFK weekly (you clear customs in Bermuda tho). it was 50/50 of what terminal. AND last trip specifically (when I had an Eagle connection) we were TOLD on the plane we were going to T8 and within the next few minutes that was switched to T9. Rhyme or reason? none .. its JFK!

2. Connecting time. It might work. I cannot give you the turn-by-turn instructions as it changes weekly .. The biggest issue will be getting OFF the MIA plane (big and full). Then you gotta hooof it up and out of T8 and over to T9, up the escalator (fighting checking and baggage people as you go) .. then through security (T9 has VERY ruff security to the point of belts too!).

From Security, you almost do a U-Turn and look like you are going back out again .. for Eagle .. which is downstairs on the right.

You CAN probably make it .. but it will be tight .. no extended bathroom breaks .. no getting lost .. trying for the VIP line at T9 if they have it (and if you can use it).

Is there a later flight? What are your stranding options??