The news follows the announcement on Thursday that Portsmouth will be allowed to begin the season on zero points until the club can come out of administration.
Kieran Djilali, Mustapha Dumbuya, Jon Harley, Brian Howard, Izale McLeod, Lee Williamson, Jack Compton, Luke Rodgers and Liam Walker have all signed one-month contracts.
Simon Eastwood, who played against Plymouth on Tuesday, also signs after originally playing on a non-contract basis.
Brian Howard will take on the role of captain at the club. The midfielder has been at Reading for the past three seasons and spent time on loan at Millwall last season.
Lee Williamson joins from last season's play-off finalists Sheffield United, dashing the Blades' hopes he would sign a new deal at Bramall Lane.
Former Chelsea and Fulham man Jon Harley spent last season at Notts County.
Speaking to the BBC, manager Michael Appleton said: "They are just one-month contracts, that is all we can do because of the risk to both parties at the minute.
"But it's fantastic for the players, many of which have been training with us for four weeks, but there is still a fantastic spirit and they can't wait to play."
Earlier on Thursday, Pompey got the news they needed when the League granted them permission to start the season in administration.
A League spokesman said: "Given the ongoing dialogue between the administrator and the Supporters' Trust, the board has given its consent to Portsmouth beginning the new season in administration.
"The club will start on zero points, with the conditions of membership announced at the board's previous meeting - including a 10-point deduction - not coming into effect unless and until the club exits administration."
Portsmouth's future remains uncertain after former owner Balram Chainrai withdrew his offer to buy the club, but the Pompey Supporters' Trust remain hopeful of completing a takeover.
Administrator Trevor Birch welcomed the decision, saying: "I'm encouraged by the League's decision to postpone any possible points deduction until it receives an application for membership by the Trust.
"At that stage, the application will be accompanied by a request for a review of the points deduction."