First thing to know is there is only 3 coils in a V6 coil pack..........NOT 6
In a V6 the 6 Cylinders are paired to balance the engine, so 2 pistons are at TDC(top dead center) every 120deg of crank rotation
In most V6 engines, including the 4.0l OHV, 3.0l Vulcan and 4.0l SOHC(your 2009) the pairs are:
1 and 5
2 and 6
3 and 4
And thats where the firing order comes from for any engine, the pairs
Drawing here:
https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQZ43umRaWFRb0hN3MniyLFSIcovngy8ebYr3IMiAowmyjna1ie
Coil is sideways in drawing
4 6 5
3 2 1
4 and 3 are on the same coil
6 and 2 are on the same coil
5 and 1 are on the same coil
It could be wired this way as well:
3 2 1
4 6 5
Wouldn't change a thing as long as 1 and 5 are on the same coil, 2 and 6, and 3 and 4
OR
3 4
2 6
1 5
Actual firing order is 1-4-2-5-3-6, to get the matched pairs you split firing order in half and put one above the other
1-4-2-
5-3-6
Those are the match pairs of cylinders to balance the engine, 1/5, 4/3, 2/6
To make it easier Ford just put 1 2 3 in a row and then matched them up with their pairs
1 2 3
5 6 4
The wire connector on the coil decides which end is 1/5 so where to start the "firing order"