The earliest attestation known to the OED is in Ælfric's De temporibus anni, written after 1005 and probably before 1010. The OED quotes the following passage -

Seo eorðe stent on gelicnysse anre pinnhnyte, & seo sunne glit onbutan be Godes gesetnysse.

Which means

The earth can be compared to a pinecone, and the sun glides around it by God's decree.

But a glance through the whole text (translated into modern English) will show that it's not just the one passage, but consistently used throughout the whole treatise (e.g. §1 "It is always day on one side of the earth and night on one side", §3 "Our earthly night is due to the earth's shadow", etc.).

The earliest attestation given with the exact spelling "earth" is in Richard Hakluyt's 1582 book Diuers voyages touching the discouerie of America.

Obviously "earth" is an English word, so other languages do not call our planet by that name: they all have different names for it (though a lot of them have the same meaning).

Earth is from the English "eorthe/ertha" and German word "erde", which funny enough, both mean ground. But no one knows who first decided to use earth to refer to our planet.

To answer your follow up, no. there are a ton of words to name our planet, from the Portugese "Terra" to the Dutch "aarde". But they all have one thing in common, they all refer to the ground or dirt, etc.

Hope this helps.