Hair falling out at day 9 of hair transplant, too soon or normal?

It would be best if you contact your doctor for a follow up exam if you are having issue after surgery.  There is no particular "rule" on what day the transplanted hairs will shed.   Some grafts can be dislodged few days after surgery but this is relatively rare.

Typically by 9 or 10 days the grafts (follicles) are well incorporated into the scalp.It is possible that a few of the grafts have been dislodged but most of what you are seeing is a crust of fatty tissue surrounding the graft and a little shaft of hair- meaning the follicles are safe and you can expect normal growth.

With
regard to your newly grafted hair be very careful for the first 4 days.  By day 5 you may resume most activities
however hold off with strenuous exercise for a full week.   This
timeline takes into consideration that your new grafts are well seated in their
new location by the end of the 4th day.  You may continue to rub your scalp to remove
the scabs without fear of losing the follicle. 
The hair however, within that follicle may be shed.  It is the follicle that is left behind that
produces the new hair by the 2nd to 3rd month.

For the first two weeks, it's important to be careful with washing to avoid irritating the scabs.  If an entire scab with a follicle is pulled out, it may not grow back.  After two weeks they are generally well seeded and you can generally shower normally.  

These hairs will sooner or later shed. They are never a problem for new hairs that start to grow. Usually, there is a lag time between the time the hairs shed (2-8 weeks) and the time the new hair grows (3-8 months). IF for any reason, there is an overlap between the two, pay no attention to it for when the new hair grows, the old hairs from the grafts that may persist beyond 8 weeks, will eventually shed