Singapore citizenship processing time

[Makigoh]

Hi All, I hope to find some helpful advice from u guys.
Profile: interviewed on Feb 2016,
Indonesian Chinese female 27,
In Singapore since 2003,
PR for 5 years (REP expiring in sept 2016),
Sister and brother are Singapore citizens.

1. I don't find any link or email for me to update ICA changes in my employment (changed job, also part timing with ex company). Is mailing to ICA advisable?
2. I am planning for a trip in Nov, however I am afraid it might clash with the application progress. As I read from others post, high likely results would be posted to you in about 8-10 months. How long do we need to reply upon receiving mail ?
3. I had just made booking of SOBF with HDB in May, do I need to update ICA ?

Thank you all for your time.