Sorry for the late reply, had a long day of traveling yesterday and didn't get onto the computer until just now.
8.7 amps is over the rating of the convection blower circuit. The entire module is only rated for 10 amps.
There are two options:
1) Give us a call and we'll see about getting you set up with a unit that has our external/aux fan switch on it. This option allows you to wire to the control board of you furnace and control the fan that way. It works in parallel with your existing furnace setup, meaning you do not need to disconnect the motor from it or disconnect your furnace's thermostat. This is what we recommend for those wanting to control furnace's blower.
2) You can try wiring the blower to its minimum speed. Preferably you'll be able to test the current draw with a multimeter before connecting it to the coal-trol power module. If it is below 3 amps draw it should be okay.
In either case please feel free to call us at 315-299-3589 to discuss this further.