Cestor joined Orient's youth squad early in the 2009–10 season and also featured in the reserve team before being called up to the first-team squad in December 2009, although he made no first-team appearances.[3] He signed a new two-year contract on 9 June 2010,[4] and he made his professional debut in a League Cup match for Orient, as they won 2–1 at Swindon Town on 10 August 2010.[5] His league debut came three days later in the 3–1 defeat to Charlton Athletic.[6]
On 11 January 2011, Cestor went on a month's loan to Boreham Wood,[7] making his debut on 15 January in the 2–0 win over Chelmsford City.[8]
Woking
On 19 August 2011, he went on a month's loan to Woking,[9] and made his debut the following day in the 0–0 draw at home to his old club Boreham Wood.[10] He made seven appearances for Woking before returning to Orient and coming on as a substitute in their 3–2 League Cup defeat at Blackburn Rovers on 20 September.[11] He returned to Woking on 12 January 2012 for another month's loan spell,[12] which was later extended, and after a brief return to Orient, he began yet another loan period at Woking.[13] On 15 May 2012, he was one of three players released by Orient manager Russell Slade.[14] On 19 July 2012, Cestor signed permanently for Woking, who were newly promoted to the Football Conference.[15]
On 20 December 2014, in a 2–1 defeat to Southport, Cestor suffered a long term knee injury, therefore ruling him out for the remainder of the 2014–15 campaign.[16]
Ahead of the following campaign, Cestor was released at the end of his contract, due to his slow progress with his injury.
Épinal
On 2 July 2016, Cestor joined French side SAS Épinal after a year without a club.[17]
International career
Prior to the 2013 Toulon Tournament, Cestor received a call-up for the DR Congo U20 team. Cestor went on to start all four of DR Congo's games in the Toulon campaign, initially making his debut in a 1–0 defeat against the France U20 side on 30 May 2013.[18]