We'll take a stab at one. Is #9 Sister Island?

Only visitor I know is a WACKO.
(Mombo)

Climb this tower and you can look at a Saint.
(Saint Lawrence River)

E=mc2
(Theory of Relativity - Relative - Sister)

Eight minutes to three
(252 - HL Edition number)

Retired March 31, 2001
(Limited to one year production)

And the winner is...
(Mombo chose this lighthouse in HL's register and win contest.)