You have 2 options for Singapore COC:
1) Submit your application with the request letter from IRCC for the COC, or
2) You can apply for your COC now with your ITA and a PDF copy of the CIC document checklist from the website:
http://www.cic.gc.ca/english/resources/tools/perm/express/intake-complete.asp
I did the latter. I got my COC a month after I applied for the e-Appeal, so you still have ample time before 9-Nov. I'm also a resident of SG.
For option #1, you will have to wait for the IRCC letter then apply for the COC, which will take longer time. However, this your best option if you have an accompanying spouse, who also needs a Singapore COC, since your ITA does not include his/her name, whereas it will be included in the IRCC letter.