A number of issue's , 9:11 is not correct ratio number maybe you mean 9:1 ?
Then how is it built , it can not be both a balun = balanced to unbalanced feedline or ladder line to coax , unun balanced to balanced ladder line to ladder line normally a 1:1 choke .
An ideal hight of horizontal antenna is 1/4 wave of the lowest band of interest .
Depending on soil , generally never less than 8' in ground and connected to all other house shack / grounds .
" At 7 watts am I going to have SWR issues? " If your listening , where does the 7 watts come from ?
And SWR has nothing to do with wattage output .
Generally for listening , there is not much difference in length , no way to tell at this end what you mean by ut ?
Also length of antenna has to do with frequency / band , nothing to do with what radio , mode SDR .
So for some beginning suggestions 1-30mhz the lowest band 160m = 1/4 wave in length & hight - this is difficult to achieve for most unless your in the country and room .
Since your just listening and if you have the room = min. 1 wave length long if not multiple wave length long and about 6-10 off ground , you may want to look into what's called a beverage antenna , one of the best for low noise & low band 40m being on the high side .
Which may require a 2nd antenna , for 40m & above ?
But for listening with SWR , most anything will work 20-30 feet long & high fed at one end into shack , using a non-inductive resistor about 10K ohm for static , noise , lightning protection / ground connected .