I'm not related but am familiar with Kent County, Delaware. 1800 and 1810 Census lists one person with this name but there is no record of his grave in Kent County Cemetery Records (Dill, Dill & Dill - 1989). Perhaps there was no marker. Nothing using spelling variations either. In fact, there were only two Shaver's listed and it appears to be a monument for a couple still living.
Probate was reported in one family tree that shows his parents as Peter (1714-1762)and Ann(1718-1789). David's birth listed as 1760 in Delaware. No source citations other than Census. Citations for Thomas Shaver support that he was David's son - born DE and married OH.