Do I Really Need 2 amps

As d1 has said, usb3 can supply 900ma. If you just plug the tablet into a dumb charger, it will only charge at 100ma.
I found that a dumb 1amp charger plugged into a usb3 hub can charge at the full 900ma.

Yet another reply..
If you use that jaycar adapter, it may work, but some devices need to talk with the charger before it can charge at the higher rate.
My discovery was that a cheap usb3 hub from Woolworths did the talking and allowed faster charging. 100ma is next to useless.

A device attached to a PC-based USB host may only draw 100 mA upon initial connection and should only proceed to draw the full 500 or 900 mA if it manages to successfully negotiate this with the host. The current provided is not actually limited by the USB host, so the responsibility for adherence to the power negotiation protocol lies with the device manufacturer. A well-behaved device should limit itself to 100 mA if it doesn't manage to negotiate higher current draw.

However, the USB standard also specifies a dedicated USB charger. A (modern) device recognizes that it's attached to a charger, because, unlike a standard USB host, the middle two lines of the USB connector (D+ and D-) are shorted together. When the device detects that it's connected to a charger, it can commence drawing the full amount of available current right away, without the need for power negotiation.

It's a familiar topic, because not too long ago I ran a small business that designed and manufactured certain USB devices and hosts