Isopropanol in contact lens solution plastic bottle
Based on your description, it looks like you've determined both plastics correctly. In general, they both would work fine for storing isopropanol; however, according to the Thermo Fisher's Labware Chemical Resistance Table, HDPE is preferred: 

$\ce{i-PrOH}$ – PET


$\pu{20 ^\circ C}$: E Little or no damage after 30 days of constant exposure;  
$\pu{50 ^\circ C}$: N Immediate damage may occur. Not recommended for continuous use.


$\ce{i-PrOH}$ – HDPE


$\pu{20 ^\circ C}$: E Little or no damage after 30 days of constant exposure;  
$\pu{50 ^\circ C}$: E Little or no damage after 30 days of constant exposure.