The short answer is probably not.
When you install iOS 8 tomorrow, part of the setup will ask if you want to upgrade to iCloud Drive. That same screen will also list devices attached to your iCloud account that will not yet work with iCloud Drive. Namely, your Mac running OS X Mavericks will not be able to sync with iCloud Drive. iCloud Drive is simply not backwards compatible with the Documents & Data portion of iCloud sync that we've been using for years.
In about a month's time we should have OS X Yosemite, which will work just dandy. That is the time to embrace iCloud Drive. If you use OS X Mavericks (or an even earlier version) iCloud sync will permanently break on that Mac once iCloud Drive is enabled on an iOS 8 device.
Don't get me wrong here. iOS 8 should be a fantastic upgrade. iCloud Drive will be fantastic, too — when all your devices are ready for it. It's just that tomorrow is probably not that time, unless you only use iOS 8 capable devices.
Last year, with iOS 7, Apple held off with iCloud Keychain until OS X Mavericks' release. I wish they had done the same with iCloud Drive, as the ability to sync between your devices seems like something pretty important.