Hi Saurabh,
If your admit card is not released by the school, there can the following reasons:
1. You may be having your pending dues that needs to be cleared.
2. You may be having a book issued from Library that has not been deposited back yet.
3. There may be some error while your application was being filled at board's website.

Don't be panic. Just ask your school teachers or reach out to the principal regarding the same query and your passing or not in the practicals will be dependent on your knowledge. So do study well for the same.

If the problem still persists, then you can reach out to CBSE board helpline details that is 1800-11 - 8002.
Feel free to contact me for any further issues.