It's been 8 days since my eyebrow transplant. My eyebrows are very itchy and I have clumps falling off (Photo)

Patients can typically start to note timeframes for their healing and results around 2-4 days after their eyebrow transplant procedure. The itchiness and scabbing develop and fall away around the third to fifth day following this initial period. 
At the 8th day post-procedure, this is likely to be a normal occurrence. But please also report your concerns to your doctor. An antibacterial ointment may help with the itchiness. The clumps of hair falling off do not mean that the actual follicles were affected. These are just the hair shafts. The follicles are getting rid of the old hair to prepare for new growth.
You can see an example of a fully healed eyebrow transplant in the link below, and also in the video. 

You can use a gentle conditioner to remove scabs, and to deal with the itching just dab instead. Always consult with your doctor about post-op instructions

Itching in your case is likely due the amount of scabbing you still have.  By 8 days my patients rarely have any scabbing because I instruct them to start washing them after 48 hours.  Good luck, and I hope you get the results you are looking for.  Best, Dr. Rome

An eyebrow transplant is treated just like a regular hair transplant with regard to the recipient area, but the donor area has open wounds which require daily washing with soap and water. Within 3 days of surgery, you can resume full activities, heavy exercises if you wish. The recipient area requires daily washes as well to keep the recipient area free of crusts. I generally recommend the use of a sponge and supply my patient with a surgical sponge to fill with soapy water and press on the recipient area daily. By repeating this daily, all crusts can be washed off without any fear of losing grafts. IF any crust is present, use a Q tip and dip it into soapy water, and roll it on the crusts and that will lift them off without dislodging them, but never rub them, just roll the Q tip on the recipient crust. I like to see no evidence of any crusting in the recipient area and the crusts from the donor area gone in 3-4 days with daily washing. To get the crusting off, you need to leave the shampoo on your hair for 10 minutes and as the crust become water logged, then will come off with gentle finger action. Repeat this twice a day until it is all gone.