I'm not aware of any "spray" adhesives that would support the weight of a ceiling tile. What do you mean by "safely"? If you are real careful, the tile won't smack you in the lips when you remove it. At any rate, liquid nails will hold it...gotta support it somehow while the glue sets....Removal??..better count on some scraping, chiseling, sanding....whatever, and uh, if your ceiling is drywall or plaster....some repairs.