More specific info about receiving credit:

A student requesting credit for high school courses taken in an approved home instruction program shall provide FCPS with a list of courses taken, the objectives for the courses, and evidence of achievement. The courses for which credit is desired must correspond to courses offered by FCPS. If the evidence of achievement is determined to be insufficient, the principal can require the student to take an examination in each grade or course for which he or she wishes to establish placement or credit. Any credit granted by FCPS for courses taken under home instruction shall be designated on the student's scholastic record as credit transferred from home instruction.
Contact your base school to schedule an appointment for registration. Boundary information is available at http://boundary.fcps.edu/boundary/.

Here's some information:

https://www.fcps.edu/registration/home-instruction

My kid is a rising 10th grader and wants to homeschool for one year.

How can he do this and get credit so he can return to school in 11th grade? FCPS.