I'm applying to private school next year and I don't know if I should take the ISEE or SSAT?

I applied to private school last year trying to get in for 9th grade but I was also applying for financial aid. I took the ISEE and my scores weren't good. I studied for the test but I found it very difficult. My grades are good though overall in my 8th grade year on my report card I have all A's and one B+. My state testing scores are also very good. I had applied to 2 schools and was wait listed for both. My guidance counselor spoke to each of them and they had said if my testing scores for the ISEE were better I would've gotten in or if I wasn't applying for financial aid. I want to try for my sophomore year again because each school i was wait listed for notified me and said they were fully enrolled. So now I'm not sure if i should take the ISEE again or try for the SSAT. Which one is easier? Thanks for the help. :)