Você teria que fazer isso com um declaração preparada . Algo como:
SET @s = CONCAT('select * from ', @Cat, ' where ID = ', @ID_1);
PREPARE stmt1 FROM @s;
EXECUTE stmt1;
DEALLOCATE PREPARE stmt1;
SET @s = CONCAT('select * from ', @Cat, ' where ID = ', @ID_1);
PREPARE stmt1 FROM @s;
EXECUTE stmt1;
DEALLOCATE PREPARE stmt1;