I don't think you qualify for OHIP unless you have a full time job.
See the following quote:
Are open work permit holders and/or participants in Citizenship and Immigration Canada's Post-Graduation Work Permit Program affected by the regulation change?
Open work permit holders (including those in CIC's Post-Graduation Work Permit Program) may be eligible for Ontario health insurance coverage
provided they are employed full-time for an employer in Ontario for a minimum of six months, have a valid work permit during this time, and they:
- maintain their primary place of residence in Ontario; and are
- physically present in Ontario for at least 153 days in any 12-month period; and are
- physically present in Ontario for 153 of the first 183 days immediately after establishing residency in the province.
Taken from:
http://www.health.gov.on.ca/en/public/programs/ohip/ohipfaq_dt.aspx#4