Bachelor Thesis supervisor in a CV? I am currently working in a research laboratory in a University under the leadership of one of the university professors. This professor is in charge of several students doing their Bachelor Thesis but sometimes he delegates the supervising work to me and then I supervise some students during the whole thesis.

I do not mind doing that, I liked. My question is if this task can be added in a CV or if it looks not professional. How can I add or explain it to add it in a CV? I am interested in add it as a personal skill (something like thesis supervising) and academic (supervisor of project X)
You can certainly add them to your CV. There's no general rule on how to write CVs so it's more or less personal preference. For an academic CV, teaching might be an important point, so I like to include "teaching experience" as a section but I prefer only mentioning "supervision of 5 bachelor theses and 2 diploma theses", otherwise it would get quite long.

In the end: if it makes sense and the information provided shows your qualification for the job then you should include it.