Depth comes with higher grades. I wouldn't be too alarmed at his progress. The lower grades are incredibly repetitive, the progressions from one grade to the next are not significant.
My son's intellectual curiosity is limited by his expectation that everything should be easy. He's a naturally lazy guy. 😂 He is motivated by acceleration though!
I vote to let your son go. Let him learn at his pace. Don't worry about flying through grade levels because Common Core instruction is incredibly repetitive between grade levels. He'll eventually find something which is academically challenging - and the sooner he finds that, the better. The younger he is when he struggles, the more you can guide and influence him through it.
My son skipped 2nd and 3rd grade math, half of 4th grade math, half of 6th grade math, and also is skipping 7th and 8th grade! Math is not his strength. I'm not bragging on my special-snowflake brilliant kid. I'm illustrating how repetitive Common Core standards are.
I suggest figuring out your "worst" case scenario, and making long-term academic and social plans for if he continues to progress at this pace. Understanding my son's academic options relieved some of my anxiety, and helped me figure out how to have my son in middle school, high school and college level classes - all at the same time!
What options do you have if your son completes one grade per year and he graduates high school at age 15? What options do you have if he completes 2 grades per year and graduates high school at 10 or 11?
Below is a list of things I've done to figure out what is available for my son.
Find out what options are in local district,
Learn my state's laws and loopholes.
Investigate under what circumstances my district might pay for college courses
Join the charter school board
Decide whether early university (living away from home) or gap years works better. State child labor laws influenced my decision, as did the state's legal definition for compulsory school attendance
Investigate my state's requirements for homeschool and under what circumstances it might work for my family
Investigate what the local community college and nearest state university require for early entrance
