I don't believe the MAX 9 would give VA what they are wanting in terms of a 200 seater aircraft, and wouldn't be enough of a bump in capacity to justify a new sub fleet.
The main issue with the MAX 9 is that it doesn't increase seating capacity that much. Based on the technical specs published by Boeing, it only provides around an extra 15 seats compared to the MAX 8. Whereas the MAX 10 is around an extra 25-30 seats.
Obviously, this is dependent on the chosen configuration. More premium seating will reduce the bump in capacity that can be achieved.
Comparing some -8, -9 and proposed MAX 10 seat counts:
| 800/MAX 8 | 900/MAX 9 | MAX 10* |
| Alaska | 161 | 178 | 188 |
| United | 166 | 179 | 189 |
| Delta | 160 | 180 | 182 |
| Aeromexico | 166 | 181 | - |
| Copa | 166 | 174 | - |
| WestJet | 174 | - | 196 |
| WestJet (abandoned densification plan) | 180 | - | 212 |
| Virgin | 182 | - | - |
| Ryanair | 197 | - | 228 |
I think the WestJet densification plan is the closest comparison to the current VA layouts. On their -700 and -800 layouts, there is a difference of 2 seats, with WS having an extra row of business class.
The MAX 9 has less range than the MAX 8, and given the issues with bilateral agreements as mentioned above by HS-TQE, I don't see VA using larger gauge aircraft on much international flying purely because of the lack of available seat capacity. Indonesia was, and will soon again be, maxed out. Fiji is maxed out. Runway limitations would likely rule out Queenstown.
Any use of larger gauge aircraft on their international network would have to come at the expense of frequency, which is somewhat important to maintain when their competitors are flying multiple daily flights.
Also, it's worth noting that the MAX 10 is probably going to kill the MAX 9. Alaska and United are the biggest MAX 9 operators. Alaska is only taking the -10 (and a small batch of -8s) from here on out. United's MAX 9 deliveries wrap up in 2027 and only expects to take -10s beyond that point.