I mean, it's the space-time continuum, it's connected! As the documentary Stargate SG-1 shows, we're well acquainted with spatial and chronological drift over interstellar distances.

If you travel 6 month to the future, you are still in the point where you started, but the Earth will be on the other site of the Sun.

Why would you remain spatially locked to the sun? The solar system is moving around the milky way. The Milky way is traveling at around 370 miles per second if we use the universe as a frame of reference. A point is both a place and a moment. Everything is moving relative to everything else. Time travel is also space travel.

This is a huge assumption. Why is it necessary that time would not have a space reference? I'd actually say that based on relativistic physics there probably is a space reference because the dimensions are linked. I think it's possible that the momentum of the current movement could remain constant and thus stick the time traveling device to the earth. Coming to a complete referential stop in space would require beyond immense energy and be inefficient if one only wants to travel in time

Kinda depends, doesn't it? A travel that let's you see glimpses of reality/earth implies you're making smaller skips that may keep you somewhat held in place. Being able to establish a vector through time may also imply control of vectors in space.

Also, six months would likely take us farther than the other side of the sun. If we're completely de-referenced we might be able to find a universal reference frame or some wild shit.

Being human sucks.

Perhaps designated Time Travel zones that are kept clear year round and only allow jumps of exactly one year?