Run forward. All the enemies are in your way. You'll just need to make a small jump to bop a piranha plant in a pipe, which you can then just fall off to take out a Koopa Troopa for your tenth point.

If you have perfect timing, you can shave a few seconds off your time early with two perfect jumps. First, try to jump over the piranha plant, rather than going off the pipe or waiting for him to go ...