How I can safely develop my chest more after a shoulder dislocation? (slap tear, 6 months ago)

Be careful with. Press exercises. The best treatment would be to focus on higher repetition and lower weight exercises. Also have a spotter in the event you struggle. I would really try to avoid struggling and maxing out.
Strength training. First of all usually after an anterior dislocation it is the anterior labrum that is affected, not the superior labrum. Secondly, you don't say whether it was surgically repaired. If no repair then the slap might be incidental finding on mri. Avoid extremes of external rotation, for example bench press.