Not considering any of your fit data, a Specialized Roubaix in a 56cm will be 4.5 cm higher in stack than what your 56 cm Caad 9 is. A Cannondale Synapse in a 56 will be 3cm higher than your Caad. As for going bigger, at your 182cm I'd think you'd be shown in the 58 cm size of bikes by most. Or at least between a 56 and 58 cm bike. And you might try bigger still.

But the larger you go, the more stretched out you'll get and will be back in that more aero position you seem to not want. I'm not the limberest person around and I can't even get my hands halfway down my shins with my legs straight. But after I turned 55 I found I liked the more aero position on road bikes. I can ride them farther than I can on a upright sitting bike. IMO, the more upright the position the more weight you'll have on the saddle. And that'll make for a sore but after 60 miles.