First convert the total length of the journey from kilometers to meters: 9 kilometers * 1000 meters/kilometer = <<9*1000=9000>>9000 meters
Then divide this by the length of one step to find the number of steps in the journey: 9000 meters / 3 meters/step = <<9000/3=3000>>3000 steps
Then multiply the number of steps by the number of flowers per step to find how many flowers one unicorn creates on the journey: 3000 steps * 4 flowers/step = <<3000*4=12000>>12000 flowers
Then multiply the number of flowers per unicorn by the number of unicorns to find the total number of flowers created: 12000 flowers/unicorn * 6 unicorns = 72,000 flowers
#### 72000