@googlimoogli Yes you can.
My son is in a similar situation as a Spring admit to USC with admits to other schools for Fall. We emailed USC and asked whether it was OK to deposit to another school on May 1 while waiting until mid May to find out if bumped to fall at USC. They said it was fine if we only wanted to attend USC if bumped to fall. That said, I now think Spring admit may be a blessing since it is likely no school will open normally in the fall anyway.