How much current can my double pole breaker supply?
Common misunderstanding.  If you supply your sub-panel with 90 amps at 240 volts, that's what it will have.  You'll still have 90 amps available on 2 legs at 120 volts. So yes, you'll have 180 amps available at 120 volts (90 amps on each hot (leg)).
If possible, can you run your table saw and compressor at 240? Many motors can easily be converted from 120 to 240 with a simple wiring change.  See the face plate on the motor for instructions.  If not, be sure they are on separate 120 v legs. And just because the instructions for a table saw says it needs a certain amperage, the reality is tools like a table saw rarely draw their full load.   I know others here tend to over-kill the supply, but I'm a bit more realistic to real-world considerations.