I've been wanting to change my name for a long time. I hate my name. But it takes a while for a name change to officially go through (about 90 days) and I want to find work now. Can I use the name I want until it goes through or will that ruin my chances of getting the job?

Your name will not match your social security records. They will not hire you based on that alone. You will have to go through the ENTIRE process under your old name, and change it later.