Party Alignment and Player Count advice?

[Gwazi Magnum]

Basically with the school year ending soon (For college/university students) we are starting up another D&D campaign for the summer.

But we've hit two main issues atm.

1. We hit a total of 9 Players + DM

Mainly it started as 5 people, but we were already used to 7. So one of our members extended an invite to a friend of his who we all got along with to join making us 6. Then three other friends of ours later (also people we've role played with in the past) showed interest & we wanted to be able to play with them cause it was a long time since we got to, which knocked us up to 9.

Main concern's here are mainly slow combat, giving everyone a time to shine and contribute, and everyone's role/job to be useful and somewhat unique to the others.
(On the bright side, this is probably a rare case where it's safe to separate the party :P).

2. We're used to evil campaigns, but this time a few players want to go good.

Now I know the bad rep evil campaigns get, and most people are used to good ones and find the evil ones as odd and needing advice for. Me and my group is the reverse, we're used to being chaotic, having insane plots and screwing over NPCs for experience or financial gain. I can imagine the temptation of cashing in big and/or just having a chaotic moment too tempting for some people to do well in a good campaign.

So I'm wondering what tactics do you guys use to keep players engaged in a good campaign and being good characters? Even for those who prefer evil settings?
Without simple DM Intimidation/Railroading/Hijacking/Control etc. As in, ways to actually make players want to be good rather than be forced too?

If all that fails, what do you think are good ways to keep a party of separate alignments together?
Especially in cases such as say one want's to take over the world, the other is a protector of peace, law etc?

[Story]

If all that fails, what do you think are good ways to keep a party of separate alignments together?
Especially in cases such as say one want's to take over the world, the other is a protector of peace, law etc?

In my last campaign, we had a party of 3 that covered all 6 alignments (LG, CN, and NE). I think it's mostly a matter of making sure the players aren't too obnoxious. There's plenty of IC reasons why characters of different alignments would adventure together, it's the OOC that's the problem.

[Melville's Book]

I'd actually recommend making two separate games of this if the person running it (is it you? I couldn't tell) can handle that. This actually works out well, as the people who want to play Good don't need to find IC reasons to excuse the actions of evil party members.

As for what makes Good good, well, for starters, if you need a material benefit for Goodness you're already doing it wrong. However, one of the biggest benefits of playing Good characters is your relationship with NPC allies. In an Evil game, if a mobster organization pays off the town guard to help in a manhunt for you, you're pretty much on your own and can't trust anyone. Good parties usually have Good connections that they haven't screwed over, meaning they might have a safe place to lay over or receive military help from the kingdom they saved. That sort of thing.

For the most part, though, Good is about not taking the shortcuts or the easy paths to power. Good is about holding to your ideals and doing the right thing even when it's not the smartest or most lucrative idea. It doesn't hurt to toss in some tangible rewards, but the real reward for being Good is seeing the supposed widow's tears of joy when she's reunited with her husband, it's feeling the sense of triumph when you break the slave trade even though you could've gotten in on it, it's the peace that comes with sacrificing yourself for something more important than yourself.

Good isn't easy, and to some people it's understandably not as fun. But Good is about long-term rewards, not trivial things like pocket change and fleeting visions of power.