Excited as he is, his agent would have told him not to tip his hand until terms had been agreed, at least in principal, so he would not have said what he said after the match on TV, nor to the Telegraph like this, unless the deal was all but signed and done.
His wife coming here is a BIG thing. Of course he will want to find a nice community to settle in to as well, so one presumes he has this sorted already.
Most Super Rugby contracts are announced in December to February, just before/as the season starts, so I expect Wasps will make a press release sometime soon. Such things always take their time. Look how long it has been since we 'knew' that Launch is staying, but still nothing 'official'.