I just finished 9th grade & on my report card I have all A’s & B’s except one 77 for my 3rd nine weeks geometry. My semester & end grades for geometry are still b’s. Will this one c ruin everything and/or will colleges even look at it since it’s not a semester grade? I only got the C because my teacher graded a test wrong then said it was too late to fix. 
Schools likely will never even see the interim grade, only the finale. Even if it was the final grade a single C would not have ruined everything, especially in your freshman year. Moreover, non-elite schools wouldn’t even be terribly put off by a single C. Heck, lower tier schools admit people with C averages all the time as do community colleges.
Even at elite schools one C isn’t ruinous, especially in Freshman year. One caveat is that I did once hear a Stanford admissions office say that anyone with even a single C had to have the agreement of a majority of the admissions committee as opposed to others who could be admitted just by the admissions officer in their region. You’ll note that even at Stanford, easily on of the most selective schools in the country, a C isn’t ruinous, it just adds an extra hurdle and not a large one at that.
Ok thanks 
No. Short and sweet.
Colleges will only see the final grades, definitely not the C. You are all set!
No way! I have 2 C’s on my transcript (just finished junior year) but they really haven’t hurt my GPA all that much. You’ll be fine