Failed hair transplant surgery. What should I do? How do I repair it? (photos)

You need to go to a hair transplant surgeon who specializes in repair work to get this fixed. 

Yes, I tend to agree with Dr. Rassman that there are some easily to detect issues with your results that suggest a less than ideally performed hair transplant.  Just for your edification, there are at least 4 wonderful hair transplant experts in the NYC area-  besides myself, that also includes Dr. Robin Unger, Dr. True, and in CT Dr. Boden-  and others.  Do your homework and look for an expert.

Although you are not at a full year from your procedure, I share your concerns based on the pictures that I see. The grafts do not look dense enough or like they were placed at the appropriate depth. The good news is that this can be improved. Some of the existing grafts might need to be removed in addition to adding more grafts to improve the density. With the combination of the two you should ultimately be able to get a great result. 

It can take up to a full year for final results so you may see some improvement.  You say it's nine months, but your previous posts say your surgery was done on August 11, 2018, so you're really only at the six month mark.  It is still too early to use the term 'total failure'.When starting at an area of no hair, it is not unusual to need two procedures to match the density of the native hair behind it.  Give it at least two more months, then visit your surgeon to review preop photos and discuss further options.  A second procedure, or scalp micropigmentation, or both may help you get the results you desire.

From what I see in your pictures, there is not only a failure of some of the grafts to grow but there are large grafts in the frontal hairline reflecting that your surgeon didn't know what he/she was doing. Get a good second opinion from Dr. Robert Bernstein in NYC as he is very experienced and possibly the best surgeon in NY