droid...same as all other droids..except NIT one resides on nokia...
i was reading adroid SDK and gues what, i was searching how to crate service - daemon to run in background and do some things, so, i found something and, guess what was it about...(yes, you already know...damn "app in background") <- is that "multitasking model"? or?
right?
anyhow, it's not about what n9 don't have, it's more about what has been blocked on n9...i think

//edit:
folks, i am symbian user since 2006. and it is real multitasking os, and apps really runs in background and foreground and it is not just belle, but take s60v2 it will do same (with 16mb of ram...)
every symbian device have "menu" button, that button is used for switching to "launcher" or if held longer for invoking task switcher, so, in case you have some older symbian device...check it out and compare to ICS