Turn off power. Open the blower compartment so you can physically hold the blower wheel. Move the blower wheel right/left and up/dowm relative to the blower motor shaft axis. Do you feel excessive play... does it wiggle? Spin the blower wheel by hand. Does it spin freely and very quietly, continuing to rotate for several seconds? If it's quiet and no play, then I would say the motor bearings are okay.
Check the blower motor mounts. Usually there are some rubber 'feet' that help absorb vibration. Lastly turn on the power with the thermostat set to less than room temperature (no call for heat). Leave the blower compartment door open. Examine the blower compartment for a switch that's closed when the door is in place. Find that switch and make sure it's open (no power will get to the blower). Now at the thermostat call for FAN only (Fan set to ON). Now go back to the furnace and, by hand, CAREFULLY close the switch you found at the blower compartment. Make sure you stay far away from any exposed wires attached to the switch (120 volts AC). You should see the blower motor start to rotate. Watch and listen. Tell us if you notice anything odd.