Checked lugague for Bullet train and train ticket

Will my checked laguague reach before me if I take the bullet super fast train? Also how much eariler do I need to go to the station so tahat my checked lugague reaches before me in the slow trains?

Also do I need to buy yhre tickets in advance or can I buy them at the station. (will the price at the station be the same as online?)

Thank you in advance for your help.