My mother died of kidney cancer at age 71. Is this hereditary? Should I have yearly scans?

It depends. Kidney cancer at a later age like in your mother's case is more likely to be sporadic than familial. Other factors to consider include asking if anybody else in your family has a history of cancer including kidney cancer. If nobody else has a history, i would recommend your routine yearly doctor visits, screening tests, etc. Yearly cts would be most likely be overkill.
Renal cancer. + family history increase risk, known hereditary risk like von hippel lindau syndrome has a higher risk. 50% are sporadic , incidental findings. You should get annual urinalysis (check for blood in urine) , see md if having flank pain, a palpable abd mass, bgross blood in urine. No smoking. Avoid obesity, hypertension, . Get screen for mutations. Don't know about yearly ct. Talk to oncologist.