Couple of thoughts - first, welcome to the fold! This is your first post.
Second - don't know you well....... so I'll only go by what you wrote and your post count.
Many believe the C-9 is not too big to carry - see post above re: full size 1911. It comes down to how you are going to carry, where, etc. There are holsters that will work well with the C-9 and others here can provide that info. I don't carry a C-9 so don't need carry holster here.
Input on carrying..... you need to qualify the gun before trusting your life with it. Many do carry C-9 with confidence - but do not trust your life with it till you put around 500 rounds through it, and a healthy dose of your carry ammo WITHOUT ISSUE! That means perfect. The C-9's take a few hundred to break in anyhow, and you really want to know when you'll need it, it will be there. I've been fortunate in that mine will eat anything - but some have found out that theirs won't, so you may have to trial a little bit. Key is - you're carrying for a reason - so be SURE!
If you know all this already, please don't think I'm preaching - I went through this learning from others here, and I want to pass it along like was done for me.