I was a full time student from Jan-May, but started a job in September. If I file as a student, seems I'm no longer eligible for the retirement savings deductible?

That's correct. If you were a full-time student for any portion of at least 5 months out of the year, you are not eligible for the credit in that tax year. 

Technically I graduated in May and only attended classes till mid / end April. Can I remove my status as a student in order to get the retirement savings deductible, or would you not recommend that?

Are you not eligible for any education credits? You do not want to lose those.

You're right, got it! Thanks