From brief online research, hopefully correct - corrections and additions requested:
The excerpts shown in screenshots below are from the History of Brunswick, Topsham and Harpswell: including the Ancient Territory Known as Pejepscot, written by George Augustus Wheeler and published in 1878.
Jotham Stone may have been the Jotham Stone who was born at Bath, Maine, in 1778 and died at Brunswick, Maine, in 1823, where he is buried in the Pine Grove Cemetery with wives Bridget (Walker) Stone and Nancy (Whitwell) Stone. Jotham's son with Bridget (Walker) Stone, Timothy W. Stone, is buried with them. It appears that his mother may have died at his birth. Jotham was a merchant at Brunswick, Maine. He is the last person mentioned in the excerpt below.
William Hunt may have been the Harpswell, Maine, privateer who sailed the Sea Flower, or perhaps the Brunswick, Maine blacksmith or another William. An excerpt about the Hunt family from the History of Brunswick, Topsham and Harpswell: including the Ancient Territory Known as Pejepscot:
William Hall - an interesting blog series about an orphan grave marker for a Frances, found in the Stowe house at Brunswick, Maine, notes that there were numerous William Halls at Brunswick, one of whom married a Fanny in 1808. (No, it doesn't appear that the stone belongs to this Frances.) There are two William Halls buried in the Pine Grove Cemetery at Brunswick, Maine, but neither was alive in 1809. Hopefully a reader will have more information about which William Hall might have witnessed the note.
If you have have more information on Jotham Stone, William Hunt or William Hall, please leave a comment or contact me directly.