And are those numbers normal? 8% proficient in math and 16% proficient in English?
Is it that they make the test overly hard or are a majority of kids not proficient in English and Math?
They are (sadly) normal for that district. Most kids there struggle with basics for their grade level. The district I'm in now has 81% proficiency in English and 79% in math. And that's considered very high.
That particular school district has a long history (25+ years) of being shitty. I couldn't tell you what exactly is causing it, but the poverty of the area is obviously a big factor. Too many parents struggling to get by means they can't spend as much time (and certainly can't spend the money on tutors) to help their kids at home. Kids with learning disabilities don't get diagnosed, and if they do the parents & teachers aren't trained on how to properly support them.
The actual facilities are rundown - my first classroom there when I was a student teacher had pieces of cardboard covered in garbage bags placed into some the window frames after the glass broke. The roof was leaking when it rained hard. We didn't have enough textbooks for everyone, and I heard the high school literally didn't have enough seats for all students (some kids sat on floors, or on countertops). The cockroaches freely ran around in the hallways and the bathrooms. There was one copy machine for all the teachers and the staff to use, and due to funding cuts teachers had to buy their own paper if they wanted to make copies. There's no money for anything.
The worse the school district gets, the harder it is to get quality teachers. And many of the quality teachers who are there leave within 5 years, because why put up with the nightmare of working there when neighboring districts pay more with less hardship?