It depends what they mean by 90w. That could easily be average current drawn over a 24 hr period with door closed etc etc. Important numbers are current draw whilst running (ie actually working) and the current draw whilst starting up. (which depending on type of fridge, pump etc can be upto 6x continuous draw)
But,as I, ve said to Danidl, go ahead buy a 1000w inverter to run your fridge. We scrapped plenty of inverters years ago going through this procedure. If you want to run domestic fridge on an inverter get a 3kw one, or if you like buy 3 or more 1000w ones which should do job but won't last a month. Been there, got the tee shirt.
I, ve only had 35 plus years fitting boats out.
Danidl and yourself might have all the theory but when you are really dependent on something working you fit what you know works. I know 3kw inverters work fridges, any of them. I know 1000w ones don't. Fact. But, makes no difference to me. Go ahead, waste money on cheap 1000 inverters because you think they should work. Just. But they don't,not for long anyway.
This actually recommends 10x continuous (running) power for inverter sizing.?!??
Or listen to Danidl who has yet to fit out a yacht, barge or van with a working system. I, ve done at least 50 and lived in one I, d built for 5 years.
But its nice to make your own mistakes.