How to get iWork and iLife after upgrading to Yosemite from Mavericks?
It is not about iCloud account but about Mac Apps store logged in account and upgrading said apps under it.

If you have iLife and iWork trials installed under Mavericks you will get them associated to your Apple ID logged into App Store. Can't say for sure but maybe you have to update them for this. Don't have to download them all the way though when they started updating.

And no there is no way to do it except having Mavericks. You might use another Mac with Mavericks for this (provided it doesn't have iLife and iWork already installed of course) or you might install Mavericks on your Mac — you can create a temporal partition for this, you can use external drive, USB or even SD card for this too.