How wide open did you have the throttle? I could only get my H9 Alpha trainer to trim level at 1/2 throttle. Mine always climbed at full throttle. I adjusted the elevator clevis to actually have a little down elevator when the trim was neutral. The result is I get level flight at 2/3 - 3/4 throttle, slight climb at full throttle, and slight descent at anything below 1/2 throttle. This also helped me with landings as the H9 planes tend to float alot during landings.

But I suggest taking your plane to your local club/field and having some of the more experienced folks take a look at it.