Thinking of this another way...8 or 9 targets per game as you suggest = 128 to 144 targets over a 16-game schedule.
In 2004, only 15 WRs in the league were targeted 144 or more times, and only 21 got targeted 128 times or more.
http://apps.footballguys.com/wrtargetsfinal.cfm
1 Chad Johnson Cin 178 11.1 32.8% 95 53.4%
2 Laveranues Coles Was 173 10.8 32.6% 90 52.0%
3 Derrick Mason Ten 168 10.5 27.4% 96 57.1%
4 Muhsin Muhammad Car 167 10.4 30.3% 93 55.7%
5 Darrell Jackson Sea 166 10.4 30.0% 87 52.4%
6 Joe Horn NO 159 9.9 28.6% 94 59.1%
7 Eric Moulds Buf 157 9.8 33.9% 88 56.1%
8 Isaac Bruce StL 155 9.7 25.8% 89 57.4%
9 Chris Chambers Mia 151 10.1 25.1% 69 45.7%
10 Marvin Harrison Ind 150 9.4 26.6% 86 57.3%
11 Drew Bennett Ten 148 9.3 24.1% 80 54.1%
12 Donald Driver GB 146 9.1 23.4% 84 57.5%
13 Javon Walker GB 146 9.1 23.4% 89 61.0%
14 Rod Smith Den 145 9.1 27.1% 79 54.5%
15 Jimmy Smith Jac
145 9.1 26.6% 74 51.0%
16 Jerry Porter Oak 143 8.9 23.6% 64 44.8%
17 Andre Johnson Hou 142 8.9 29.8% 79 55.6%
18 Torry Holt StL 141 8.8 23.5% 94 66.7%
19 Terrell Owens Phi 133 9.5 23.1% 77 57.9%
20 Michael Clayton TB 130 8.1 24.3% 80 61.5%
21 Reggie Wayne Ind
128 8.0 22.7% 77 60.2%