Not entirely sure of the exact query, but will give it a shot.

But first, how are you getting the 36+ business class seats available? a J9C9D9I9 just means that CX is willing to sell 9 seats at the each of those fare classes- just that.

Not necessarily mutually exclusive, and impacted by stuff like married segments and point of sale.
A single sale could, possibly, change things to J8C8D8I8, or something else.
Infact, in theory, there might be <9 seats left in the biz cabin and CX could still be showing J9C9D9I9. (though i would 'expect' all 9s to imply a relatively light loading, especially if F/PE/Y are light too)

Not sure about the bit about transferring the miles - are you moving miles from a partner into your Asiamiles account?

The way CX would work is to give you a deadline (possibly extendable) and if the waitlist clears by then, give you a bit of time to issue the ticket (and deduct the miles, charge the card). If you are looking at this online, you can make the waitlist reservation, and the page notes:

Asia Miles and taxes/fees/charges/carrier surcharges displayed above are for reference only. Asia Miles and taxes/fees/charges/carrier surcharges required will be quoted at the time of ticket issuance.

So go ahead and waitlist away!