How Far out do you need to go....

from Del Monte Beach to have a resonable chance to catch a salmon?

9.5 miles?

depends on where the bait balls are.

9.5 miles?

Oh man, that's why I hate numbers lol. When ya put it like that, 9.5 miles is far!! It's better ya say 250'-300' 

In all seriousness Mooch is right, ya just gotta find the bait ball to increase your chances. I've had some friends that have caught salmon at 100' depth.

However if ya do end up going out, I wish ya lotsa success