Let's start by putting all of this into perspective. The most you can expect from any type of vision correction surgery is the convenience of a reduced need for glasses and/or contacts. To achieve that convenience, you must accept some risk. What is acceptable risk depends upon your unique situation.
Lasik works by removing tissue from the cornea (clear front of the eye) underneath a flap of corneal tissue. The tissue removal changes the shape of the cornea, thereby changing where light focuses inside the eye. The Lasik flap "fools" the eye into not knowing it has had surgery, making the healing response muted and providing relatively quick vision recovery with virtually no pain.
A healthy cornea needs to have at least 250 microns of untouched tissue to remain stable (more is always better) and with your high myopia (nearsighted, shortsighted), it may be that with Lasik more than half of your cornea would be disrupted (Lasik flap thickness plus amount of corneal tissue to be removed). Nobody wants you to have an unstable cornea, leading to progressive myopia, fluctuating vision, and even corneal transplant.
Another possibility for a high myope who has thin corneas is a surface ablation technique like PRK, LASEK, or Epi-Lasik. These techniques do not require the Lasik flap, saving about 100 microns of tissue from being disturbed. Since there is no Lasik flap to fool the cornea, healing is slower and with significantly more discomfort. Another concern with a surface ablation technique for high myopia is corneal haze that disrupts vision quality forming as a part of the healing response. This can be muted with the application of a medication called Mitomycin C, however even a surface ablation technique may not be an appropriate choice.
The Visian ICL (Implantable Collamer Lens)
is a phakic intraocular lens. It is implanted inside the eye behind the cornea and in front of the natural lens within the eye. P-IOLs are temporary. They must be removed if/when you develop cataracts (a natural occurrence related to aging) or if the cornea is irritated by the P-IOL and the cells on the back side of the cornea diminish (endothelial cell loss).
Retinal detachment is always a concern for any high myope considering invasive surgery. The most common cause of myopia is an eye that is too long. Unfortunately, the retina membrane is rarely larger to accommodate this extended length, so there is a lot of tension on the retina trying to make it detach from the back of the eye. This can cause severe vision loss. Before having any intraocular surgery, someone with 9.00 diopters of myopia should have a comprehensive examination by a retina specialist.
P-IOLs have been available throughout the world for quite some time, but US surgeons received approval to implant them relatively recently. Surgeon skill is of absolute importance, especially with the Visian ICL, because if there is any trauma during surgery to the natural lens within the eye (even a minor bump) it is very likely to become cloudy and form a cataract. You want someone who has performed at least 50 successful Visian ICL surgeries, and more than 250 would be a whole lot better.
In light of all of this, it may be that the risk is simply not worth the convenience.