At 10% the speed of light it would take 45 years to get here and slow down from Alpha Centauri, and it goes way up from there:

https://cdn.mos.cms.futurecdn.net/7Gdct9VzQFHUYf8Ec8GXmY.jpg

Again that's exponentially beyond anything we could do and why would they even bother buzzing around inside the atmosphere if they can do that?

Unless you are saying they are popping in from other dimensions/universes and that's way beyond even FTL theory.

Earth would be a huge yawn to them. They'd catalog it and move on. Unless earth-like planets are so incredibly rare to find even with those abilities.