Health and Safety certification

Implementing OHSAS 18001 is sufficient for getting the certificate based on this standard. I'm not sure what you mean by Health and Safety certification, but in most cases OHSAS 18001 is enough.

2) How best can an employer deal with a worker who does not abide by the safety guidelines stipulated by the company in regards to the implementation of Occupational Health and Safety Management Systems?

In cases when the employee is not following the company procedures and guidelines all you can do is to warn, punish and ultimately expel the employee from the work site.

3) Kindly list down the safety requirements, procedures and policies that a company must have in compliance with OSHAS 18001 and the possible optional ones.

Here you can find mandatory documents according to OHSAS 18001: List of mandatory documents required by OHSAS 18001 https://advisera.com/18001academy/blog/2016/11/23/list-of-mandatory-documents-required-by-ohsas-18001/