I am also the 7th generation of a William Hutcheson who was also born in Ireland (Northern)about 1750 (He died in 1830 and listed as being 80 years of age. He was married to a Margaret Clendennen whom we believe was from County Derry. William had sons named Samuel, John, Robert who settled in Kentucky. From information handed down William also arrived through South Carolina (Charleston). Our William received a land grant in Logan County, Kentucky in 1796.
Would love to hear more about your Robert as there could be a link there