I'm not sure where that number comes from but I don't think it's right, and I don't think that's how La Liga is structured anyway. It's governed by an association of all of the teams in the top two flights of spanish football.
I took a look at the test bench, and the Unlambda interpreter used supports like a third of unlambda, not including input. Since 79/80 of the tests require input, it isn't really possible to solve them. The best anything did on them was 1.2%, which is 1 test.
Doing something like that is basically the only way to write unlambda: you start with a lambda calculus (or scheme or whatever) and reduce the lambdas away mechanically. (This is in the unlambda docs!)