How to manually create switches to light up a 7 segment display connected to ICs?
Depending on the type of the IC family you could use a pull-up resistor and a switch connected to ground. Switch closed = logic 0, Switch open = logic 1. Read the IC data sheets to see what is recommended. 
The current is going to be what it is. To reduce the voltage you may wish to use a regulator such as an LM7805 (for 9V to 5V). 4000 series CMOS can operate happily from 9V but other types (such as the 74HC you actually used) generally require a lower voltage. Read the IC data sheets to see what voltage range they work over and what output drive current they can handle.  In the future it's probably better to do that before connecting the 9V battery to the ICs, so you don't have to replace the ICs as often. 


Note that the common is not shown on the LED display, and you don't show any series resistors, which are not optional- you should have one in each segment line. 

Edit: Use a regulator such as an LM78M05 to get +5VDC for the chips. 

If your outputs are active-high you should have a series resistor on each. For example, for 3mA/segment and a red LED (2V) you might use 1K. The display should be common cathode type, with the common grounded. The opposite is true if your outputs are active-low- use a common anode display with similar resistors and connect the common to +5. 

Inputs can be a 20K pullup to +5 with a switch to ground or the reverse (shown below- where switch closed = 1). I suggest a series resistor of 10K as well to make it less likely to damage the chips from ESD etc. 







simulate this circuit &ndash; Schematic created using CircuitLab