I wrote "isst" and was told was correct, but the translation was shown for "ist". It's cool it doesn't discriminate between isst/ist here, since they sound too alike and both work. But it'd be cool if the translation = what was written.
is "by the table" suitable?
No. "Am Tisch" means "at the table" - as in sitting down like you're ready to eat. "By the table" would be "neben dem Tisch."