The image shown is not an image of a stars disk.This is not possible with a 14"scope from earth. It is an image of a point source of light with an airy disc resolved to some extent. As such anything transitting in front of it will not show up as a dark area on the airy disc. The dark area has to be some sort of artifact either in the collimation or in the imaging train.
Sorry, no planet.
Transitting planets can be detected using photometry techniques by amateurs but not like imaging the transit of venus etc.
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