How to play OOP vs strong player

Playing a micro-stakes MTT (although I guess similar can happen in cash), where I was to the right of a strong player and it seems everything I did was outmanoeuvred.

He went all in vs someone else on the first hand of the game putting him well ahead on the table, after this he was able to play a really loose aggressive style and with the extra chips behind him he was seeing marginal hands to the turn and calling everything. Somehow this was working for him and by the time I was forced out he was on 21K while the table average was round 3 - 4k (200/100) .

For example he called my all in 3k chips with A9o...
A9 comes up on the flop.