I am attempting a quilt starting with a 9 patch then it calls for 8" square cut in half and sewed to each side to create a square...HOWEVER, the 9 patch is suppose to come
out 8 1/2 " square, but mine is only about 8" or a little less... and it is more like a rectangle instead of a square! Do I cut it down and remake the pattern, toss it all out and start over or what??? This is a class I'm taking, but I goofed up the assignemnt that I am ashamed to go back!

Do not be ashamed. We have all done stuff like that, and the only way to learn is to figure out what went wrong and how to make it better.

It sounds as though it may be a problem with your 1/4" seam. To start at the beginning to see if we can figure out what the problem is, what is the size of each square you cut for the nine-patch?

How many of the 9 patches have you made? If this is just the first one, ask your class instructor if she/he can see what you did wrong.
If you have done several, and they are all off-square, are the triangles for the four sides big enough for the longest side? You can sew them on, then square up the results, even if that means that they are no longer triangles!
Either way, don't drop out of the class!

Or just tell your teacher you meant to do it with rectangles to be different! :D

by the way, love the blue irises in your avatar! If your 9 patches are little less than 8.5, how about squaring them up to the exact same size (even though less than original pattern size) and cut the outside triangle as called for. Your 9 patches will float just a little, but personally I think that can be very pleasing to the eye, depending of course on the original design. I have had a hard time with exact 1/4 inch seams too. Accuracy comes with practice. Hope this helps. Quilt happy and much!
PS
Bet your class teacher has been there and done that too. No quilt police are allowed to torment newbies!

When I did my block for Robert and Cathy's quilt, I had to redo it. The first one was 9 1/4 on my side instead of 9 1/2. I now have a very pretty potholder. Don't throw yours away, just repurpose it and start over. Sew two 2 1/2" short strips together. Press and measure. It should be exactly 4 1/2" inches wide if your seam is a scant 1/4". I'm getting better with my 1/4", but still have to concentrate on sewing straight.

Just to make sure I understand: You are making a 9-patch and it is not really square. Hm, I would measure each section to see what part is off.

It is possible that you cut one of the sections not to size. It is possible that your seam allowance is off.

When you have the final size of your unfinished 9-patch, cut the alternating squares to the same size and you will be fine.

I usually make sure that all of my pieced blocks are squared up to the same size.

Most importantly, you are a true beginner. Don't give up and don't be upset. Maybe it is time for you to get acquainted with the frog tool also known as the seam ripper (rip-it, rip-it) WE ALL know it well.

please go back. we always learn best from our own mistakes. surely the person who teaches the class will be able to help you figure out where you went wrong and then you can practice, practice.

My favorite saying as a teacher is, "Mistakes help us learn." If you didn't make the mistake you wouldn't have learned so much about what you did wrong and how to better understand future instructions too. It is a valuable step. Never be ashamed to admit a mistake when it only helps you grow!