You'll be absolutely fine with the N9 I'm traveling around regularly and never missed anything with my N9. The only problem on such trips are the high roaming costs, so you should try to avoid them. Solutions are like downloading maps of countries you visit in advance, save some webpages offline (e.g with Opera Browser) or, like recommended by erendorn, download a wikipedia offline solution.

There are also a lot of (often free in restaurants and sometimes public transportation) Wi-Fi hotspots around where you could check emails, Facebook or whatever you need. Of course it depends on country and location... but for example McDonalds is often very good for free Wi-Fi access

Sometimes it's worth looking into a pre-paid sim card or mobile Wi-Fi hotspot, there are good offers around (IMO Vodaphone often has good deals). But again, it depends on what you need and where you are.

Mostly I like what vi_ wrote. I'm pretty often in the US (where I don't buy an extra SIM card) and what I enjoy a lot that I can't have access to the internet everywhere - you will soon realize how relaxing that is

Have a good journey!

EDIT: If you turn off internet connection in a foreign country, make sure you also turn off certain services. Use maps in offline mode (can be changed in maps settings), turn off messaging accounts (Wazapp) and automatic sync services. Since PR 1.2 it got much better, but before, the phone was constantly asking to reconnect to the internet especially when using 3rd party software which have background services needing an internet connection.