-I have very good alignment.

-I have 9 Charisma and no followers.

-I am Tech-oriented.

All I have when talking to him is one dialog option to say "goodbye" to him. Help!

Magnus joins the party on a specific condition (besides a free follower slot, positive alignment, being level 7 or above, and being capable of normal speech):

You have to sort out the deal with the P. Schuyler & Sons by killing the Schuylers. This is best done by recruiting Magnus before you go inside, since he is interested in them as well, and then he just stays with you if you let him. If you deal with them peacefully and then ask him to join, he'll refuse.

However, since he won't even talk to you, it's possible you've done something in an odd order and blocked the required triggers completely, normally he should at least have some response about not wanting to join you.

I know from experience that Magnus's party checks are a little off even with the unofficial patch, he once joined me as a free follower, which is very out of character for him. :) So it's very likely a glitch, and if so, there's nothing you can do about it besides reloading.

If reloading doesn't help and you don't manage to figure it out, we might be able to give you better advice if you tell us exactly what you did before trying to get Magnus to join you.

Magus is a horrible annoying little git. since you're tech-oriented, you won't need him anyway. whack him and take his stuff!

Agreed. But there is one reason to keep him around, at least for one playthrough: a long and twisty side quest in which he ends up playing a surprising role.

No spoilers here, but here's one hint: to unlock the best dialogue, he's not the only Dwarf you should have in your party.

Indeed, his contributions to the game can be quite surprising.

I recommend at least one full playthrough with Magnus in party.