help plz ! time constraints

[n0199]

ok so im relatively new to all this i have a great base of knowledge but not in the electrical dept. i just moved into a nice 2 level condo and i want to use an upstairs room for this. i have old fuses in the house a fusebox with 15 and 20 amp fuses so i know its out of the question BUT there was a second box installed not long ago and it has breakers to run the dryer and a roof warmer. the roof warmer has a 20 amp breaker and the dryer i think is running 2 30s side by side. i didnt want to mess with the dryer but the roof warmer is expendable. if i was running just one 1000 watt hps on a wire ran from the roof warmer breaker to the outlet to plug in the light is that safe? im going to buy good wire and i mean the correct wire for the amps. i know the light is like almost 9 amps at power up im just assuming the 20 amp breaker will be safe while its running. also i might have to run the wire under carpet to conceal it im also assuming that if i have good gauge wire it wont pose an issue. any input would be greatly appreciated i cant seem to find anyone with this similar situation