After finishing Chen's and Ankenman's Mathematics of Poker, as well as Harrington's latest online cash book, I was under the impression that I do understand a little bit of game theoretic poker, but now I am in utter shock after getting my ass whopped in 0.5-1 Zoom. After 3600 hands (is this a tiny sample space?), I am playing with -4.8 BB/100. Besides the river suck outs, I seriously believe there are drastic errors in my play.

One thing I that I found quite surprising many players including the Pro Vivian Im do, is to call a PFR with high pocket pairs 99-JJ, sometimes even QQ, from the blinds. Can this really be an optimal strategy?

I actually solved a simple single street [0,1] game where the game allows at most 4 betting, and came out with bet, bluff bet, call, 3b, bluff 3b, 4 bet, bluff 4 bet, call 3b, call 4b ranges. Not sure whether I apply the solution to actual poker ranges correctly, but I seriously feel that 88+ pocket pairs should be in the 3B range from the blinds, definitely against stealers, to UTG raisers definitely 99+.

What are your thoughts?

Yes, 3600 hands is a tiny sample space. I'm pretty sure I had single days where I played that much of "rush" poker on FTP.

When 3betting you have two motives, get better hands to fold(bluff) or to get worse hands to call(value). If you 3bet with 88. Will worse call? Most likely not. Will better fold? Maybe 99 will fold but TT+ will call. Then what happens when you get 4bet? You have to fold. So 3betting 88( and similar hands like 99-JJ) is turnig you hand basically into a bluff and isn't the most optimal way to play it against thinking opponents.

I think that 3betting to set up a 5bet shove is another valid reason for 3betting some stuff like 88 apart from the standard as a bluff or as value.

You won't necessarily have horrible equity when you get the money in if we can assume that villain has a polarized 4 bet range with a decent amount of bluffs that he will fold.

I'm not sure how many thinking players play 0.50/1.00 Zoom, but I think our response depends most strongly on who the player is and what position he is raising from. If you were playing a full ring NL100 game against an UG raiser with RFI of 8% UG, then your 88 is probably behind and raising would be turning your hand into a (semi) bluff. If stacks are deep, you might be better off folding or set-mining your 88. (22-TT might be equivalent here.)
If the RFI is from the button, with an RFI of 50%, your 88 is probably ahead. The button might call with worse because see may see your raise as light. Some don't like to fold because they have position. Here you need to play some poker.

These are hands that should definitely be a part of your mixed strategy. Sometimes 3betting, sometimes calling. Against a completely random opponent from the btn and 100bb stacks, I think that a 50/50 mix is not far from optimal. Obviously, from an exploitative standpoint you would want to 3b more against aggro btn villain(75/25?) and call more against tighter lp and mp villains(25/75).

I think there are many thinking players in 0.5-1.0 Zoom, I play 6 handed, agree with position, probably a call for UTG and 3B for cutoff and button.