Asian Double Eyelid Surgery, for the Second Time?

Double eyelid crease formation and epicanthoplasty can be done as a revision.  There are a few nuances that need to be considered in this situation.  Making a higher crease, will or may entail a higher incision and fixation at a higher point with also more skin excision.  It is usually easier than making a higher crease smaller. 
When you mention opening the corner of your eyes, do you mean the inner or outer corners.  The inner corners are more likely the area that will open your eyes more than the outer corners from a congenital standpoint.  Asian epicanthal folds are in the medial or inner corners of the eyes. This is what distinguishes Asians from Caucasians in many Asian people and not the outer corner of the eyes. 
I have seen many results from the outer corners being cut and they don't make as much difference as when the procedure in the inner part of the eyes are done.  One thing to remember is that most Asian appearing eyes have a crease that is 3mm or less when the eyes are open.  When they are larger they begin to take on more of a western caucasian look.  There are studies that validate this assertion in the literature.
Thanks for reading, Dr Young.

Timing- 9 months is ok time to start thinking about revision, 12 months is probably a touch safer in principle especially if you're happy with the job your surgeon did.
Increasing the fold- this is possible and done frequently, the danger often is making the crease too high in the first place and THAT's more of a reason often a revision is sort coming from other places.
Cutting the corner of the eye- what's you're talking about there is epicanthoplasty, what us Korean Plastic surgeons call "front opening". It creates an impression of bigger eyes but also has the effect of Eurasianising the eyes too. But the biggest thing that give the bigger eyes impression is to add in a touch of ptosis correction which is to shorten the mechanism of eye opening with sutures, obviously this needs to be done with precision and precaution. Some times "back opening" or opening up of the corner of the eyes outward closer to your ears is done to change what we call a tilt but this is less noticeable and less of a "bang for a buck" and to be applied in only specific circumstances.
Safety- Make sure you go to see a qualified specialist plastic surgeon or oculoplastic surgeon in your area.
Wish you the best in your journey.
Dr Leo Kim, Specialist Plastic Surgeon in Sydney

The question of whether or not it is worth the time and money to have a revision procedure is one that only you can answer, but your aesthetic goals could certainly be achieved during revision surgery with an experienced surgeon.