Can a sailboat big enough for 8 passengers be controlled by a single person?

My friend had a 33 foot racing sloop with cabin (6 meter format). He sailed it alone until age 80. After that, he took friends along to handle hoisting sails, doing anchors, etc. I did that many times.

One person is okay for short trips. Best to have a second qualified person for more than a day sail. If going far from land, ditto.

Yes they can, but not all of them.

Yes. Even fully crewed yachts usually have only one person on watch at night (Been there & done that - LOVE IT)

Let's see Joshua Slocum sailed around the world single handed, so yep.

NO!

Not with out a Crew.

Here's a good Tip never ask the ARMCHAIR Admirals who have never been with in a thousand yards of a boat or ship.

Your talking about a small cargo and passenger craft which would be around 17th century so do some proper research.

Even small racing dingy use a crew of at least two or three, There some are raced single handed.

Now as for the Round The World Single hand sailing Yachts of they carry so many aids they nearly could may the voyage with out anybody on board in fact it would take very little equipment added to the list to make them fully autonomous or failing that sailed remotely.

Yes it can easily.

Yes .

With the right rigging, yes.