I've searched this topic a lot (though I don't need to file taxes for YT earnings 'till next year so I don't have personal experience) so I've read a ton of threads about people asking about their missing 1099 or what to do with it (usually confused by online tax software like TurboTax or whatever which makes it seem like you need some sort of code on the 1099 when you actually don't).
Every response to these threads has been that no you don't actually need the 1099. You simply report your income. The 1099 summarizes it for you, but if you've been recording the payments you've received (or simply check the payment history with your bank or in AdSense or whatever), you have all the information you're supposed to report.
Now this is assuming you're reporting YT earnings as personal/business income. If you've got some corporation set-up or whatever I have no idea about any of that.