Creatine is safe, used by millions of people over long years, people are talking out of their asses here.
Injectable steroids are safe as well, testosterone has been around longer than your moms, also very good scientifical studies on this.
Same goes for high protein diets, btw.
IF anything hurts your kidneys it's not drinking enough, taking diuretics, painkillers and other rec drugs.
Don't fall into a panic over this, there are so many idiots out there thinking that "if 5g of creatine are recommended, i take 20 and get more effect", and no one has gone to kidney failure over this.