There should be no 9 at the beginning of my previous post. Sorry.
9g of the moon is .166*g on earth. T pendulum is 2*pi(L/g)^.5 Because g of the moon is .166*g on earth, T moon is 2*pi(L/.166g)^.5 This goes to T moon= (1/.166)^.5*T on earth. T on earth for 24 hours is 24 hours. Convert that to seconds and multiply by (1/.166)^.5 Your answer ...
For Further Reading